The remains of a terrestrial vegetation in this deposit are greatly scantier than those of its marine plants; but they must be regarded as possessing a peculiar interest, as, with the exception of the spore cases of the Ludlow rocks, the oldest of their class, in at least the British islands, whose true place in the scale can be satisfactorily established. In the flagstones of Orkney there occurs, though very rarely, a minute vegetable organism, which I have elsewhere described as having much the appearance of one of our smaller ferns, such as the maidenhair-spleenwort, or dwarf moonwort. It consists of a minute stem, partially covered by what seems to be a small sheath or hollow bract, and bifurcates into two fronds or pinnae, fringed by from ten to twelve leaflets, that nearly impinge on each other, and somewhat resemble in their mode of arrangement the leaflets of one of our commonest Aspleniums,—Asplenium trichomanes. One of our highest authorities, however, in such matters (Professor Balfour of Edinburgh) questions whether this organism be in reality a fern, and describes it from the specimen on the table, in the Palaeontological chapter of his admirable Class Book, simply as "a remarkable pinnate frond." (Fig. 13, p. 56.) We find it associated with the remains of a terrestrial plant allied to lepidodendron, and which in size and general appearance not a little resembles one of our commonest club mosses,—Lycopodium clavatum. It sends out its branches in exactly the same style,—some short and simple, others branched like the parent stem,—in an arrangement approximately alternate; and is everywhere covered, stem and branch, by thickly set scale-like leaflets, that, suddenly narrowing, terminate in exceedingly slim points. It has, however, proportionally a stouter stem than Lycopodium; its leaves, when seen in profile, seem more rectilinear and thin; and none of its branches yet found bear the fructiferous stalk or spike. Its resemblance, however, to this commonest of the Lycopodia,—a plant that may be gathered by handfuls on the moors by which the flagstones are covered,—is close enough to suggest a new reading of the familiar adage on the meeting of extremes. Between the times of this ancient fossil,—one of the oldest of land plants yet known,—and those of the existing club moss that now scatters its light spores by millions over the dead and blackened remains of its remote predecessor, many creations must have intervened, and many a prodigy of the vegetable world appeared, especially in the earlier and middle periods,—Sigillaria, Favularia, Knorria, and Ulodendron,—that have had no representatives in the floras of latter times; and yet here, flanking the immense scale at both its ends, do we find plants of so nearly the same form and type, that it demands a careful survey to distinguish their points of difference. Here, for instance, to illustrate the fact, is there a specimen of Lycopodium clavatum, from one of these Caithness moors, that agrees branch for branch, and both in the disposition of its scales and in general outline, with the specimen in the stone. What seems to be an early representative of the Calamites occurs in the same beds. Some of the specimens are of large size,—at least from nine inches to a foot in circumference,—and retain their thickness, though existing as fragments several feet in length, with but little diminution throughout. They resembled the interior casts of Calamites in being longitudinally furrowed; but the furrows are flatter, and are themselves minutely striated lengthwise by lines as fine as hairs; and, instead of presenting any appearance of joints, there run diagonally across the stems, interrupted and very irregular lines of knobs. These I find referred to by Dr. Joseph Hooker, in describing a set of massive but ill preserved remains of the same organism detected in South Ness quarry, near Lerwick, by the Hon. Mr. Tuffnell, as taking, in two of the specimens, "the appearance of transverse knobs and bars (mayhap spirally arranged) that cross the striae obliquely. But though the knobs," he adds, "may perhaps indicate a peculiar character of the plants, they have more probably been caused by pressure during silicification." As, however, they also occur in the best preserved fragment of the plant which I have yet seen,—a Thurso specimen which I owe to my friend Mr. Dick,—I deem it best to regard them, provisionally at least, as one of the characteristics of the plant. I may mention, that while I disinterred one of my specimens from the Thurso flagstones, where it occurred among remains of Dipterus and Asterolepis, I derived another specimen from the great overlying formation of pale Red Sandstone to which the lofty hills of Hoy and the tall mural precipices of Dunnet Head belong; and that this plant is the only organism which has yet been found in this uppermost member of the Lower Old Red, to at least the north of the Moray Firth. Another apparently terrestrial organism of the lower formation, of, however, rare occurrence, very much resembles a sheathing bract or spathe. It is of considerable size,—from four to six inches in length, by from two to three inches in breadth,—of a broadly elliptical and yet somewhat lanceolate form, deeply but irregularly corrugated, the rugae exhibiting a tendency to converge towards both its lower and upper terminations, and with, in some instances, what seems to be the fragment of a second spathe springing from its base. Another and much smaller vegetable organism of the same beds presents the form of a spathe-enveloped bud or unblown flower wrapped up in its calyx; but all the specimens which I have yet seen are too obscure to admit of certain determination. I may here mention, that curious markings, which have been regarded as impressions made by vegetables that had themselves disappeared, have been detected during the last twelvemonth in a quarry of the Lower Old Red Sandstone near Huntly, by the Rev. Mr. Mackay of Rhynie. They are very curious and very puzzling; but though some of the specimens present the appearance of a continuous midrib, that throws off, with a certain degree of regularity, apparent leaflets, I am inclined to regard them rather as lying within the province of the ichnologist than of the fossil botanist. They bear the same sort of resemblance to a long, thickly-leaved frond, like that of the "hard fern," that the cast of a many-legged annelid does to a club moss; and I was struck, on my first walk along the Portobello beach, after examining a specimen kindly sent me by Mr. Mackay, to see how nearly the tract of a small shore crab (Carcinus Maenas) along the wet sand resembled them, in exhibiting what seemed to be an obscure midrib fringed with leaflets.
But the genuine vegetable organism of the formation, indicative of the highest rank of any yet found in it, is a true wood of the cone-bearing order. I laid open the nodule which contains this specimen, in one of the ichthyolite beds of Cromarty, rather more than eighteen years ago; but though I described it, in the first edition of my little work on the Old Red Sandstone, in 1841, as exhibiting the woody fibre, it was not until 1845 that, with the assistance of the optical lapidary, I subjected its structure to the test of the microscope. It turned out, as I had anticipated, to be the portion of a tree; and on my submitting the prepared specimen to one of our highest authorities,—the late Mr. William Nicol,—he at once decided that the "reticulated texture of the transverse section, though somewhat compressed, clearly indicated a coniferous origin." I may add, that this most ancient of Scottish lignites presents several peculiarities of structure. Like some of the Araucarians of the warmer latitudes, it exhibits no lines of yearly growth; its medullary rays are slender, and comparatively inconspicuous; and the discs which mottle the sides of its sap-chambers, when viewed in the longitudinal section, are exceedingly minute, and are ranged, so far as can be judged in their imperfect state of keeping, in the alternate order peculiar to the Araucarians. On what perished land of the early Palaeozoic ages did this venerably antique tree cast root and flourish, when the extinct genera Pterichthys and Coccosteus were enjoying life by millions in the surrounding seas, long ere the flora or fauna of the Coal Measures had begun to be?
I may be here permitted to mention, that in a little volume, written in reply to a widely known and very ingenious work on the Development hypothesis, I described and figured this unequivocally genuine lignite, in order to show that a true wood takes its place among the earliest terrestrial plants known to the geologist. I at the same time mentioned,—desirous, of course, that the facts of the question should be fairly stated, whatever their bearing,—that the nodule in which it occurred had been partially washed out of the fish bed in which I found it, by the action of the surf; and my opponent, fixing on the circumstance, insinuated, in the answer with which he honored me, that it had not belonged to the bed at all, but had been derived from some other formation of later date. He ought, however, to have taken into account my further statement, namely, that the same nodule which enclosed the lignite contained part of another fossil, the well marked scales of Diplacanthus striatus, an ichthyolite restricted, like the Coccosteus (a specimen of which occurred in a neighboring nodule), to the Lower Old Red Sandstone exclusively. If there be any value whatever in palaeontological evidence, this Cromarty lignite must have been deposited in a sea inhabited by the Coccosteus and Diplacanthus. It is demonstrable that, while yet in the recent state, a Diplacanthus lay down and died beside it; and the evidence in the case is unequivocally this, that in the oldest portion of the oldest terrestrial flora yet known, there occurs the fragment of a tree quite as high in the scale as the stately Norfolk Island pine, or the noble cedar of Lebanon.
[I have failed hitherto in finding any remains of terrestrial plant-covered surfaces in the Old Red Sandstone of Scotland, though decided traces of desiccated sub-aerial ones are not rare. Shallows and banks seem to have been numerous during the period of at least the Lower formation. The flagstones of Caithness and Orkney, and the argillaceous fish beds of Cromarty and Ross, not only abound in the ripple-marked surfaces of a shallow sea, but also in cracked and flawed planes that must have dried and split into polygonal partings in the air and the sun. The appearance of these in the neighborhood of the town of Thurso, about half a mile to the east of the river, is not a little curious. Bearing throughout the general dingy hue of the flagstones, they yet consist of alternating beds of two distinct characters and qualities. The one kind, fissile, finely grained, and sharply ripple-marked, seems to have been deposited in shallow water; the other, not fissile, but, if I may so speak, felted together so as to yield with difficulty to the hammer in any direction, and traversed by polygonal partings, filled up usually by the substance of the overlying stratum, appears to have had a different origin. The state of keeping, too, in which the ichthyic remains of these alternating beds occur is always very different. The smaller and more delicately organized fishes are never found entire, save in the fissile, finely grained beds; in the others we detect only scattered fragments; and even these, unless they belonged to the robust Asterolepis or his congeners,—which, however, in these beds they usually do,—much broken. The polygonal partings seem to indicate that these toughly-felted beds, whose very style of weathering—rough, gnarled, fretted into globose protuberances and irregular hollows—shows that it had not been formed by quiet deposition, must have had their broad backs raised for a time above the surface of the water, to be desiccated in the hot sun. And the fragmentary state of the fossils which they contain seems to point, with the roughnesses of their weathered surfaces, to some peculiarity in their origin. The recollection which they awoke in my mind with each visit I paid them for three years together, may probably indicate what that origin was. I had a relation who died more than a quarter of a century ago, who passed many years in British Guiana, in the colony of Berbice, and whose graphic descriptions of that part of South America made a strong impression upon me when a boy, and still dwells in my memory. He was settled on a cotton plantation near the coast side; and so exceedingly flat was the surrounding country, that the house in which he dwelt, though nearly two miles distant from the shore, stood little more than five feet above its level. The soil consisted of a dark gray consolidated mud; and in looking seawards from the margin of the land, there was nothing to be seen, when the tide fell, save dreary mud flats whole miles in extent, with the line of blue water beyond stretching along the distant horizon. These mud flats were much frequented by birds of the wader family, that used to come and fish in the shallow pools for the small fry that had lingered behind when the tide fell; and my cousin, a keen sportsman in his day, has told me that he used to steal upon them in his mud shoes,—flat boards attached to the soles, like the snow shoes of the higher latitudes,—and enjoy rare sport in knocking down magnificent game, such as "the roseate spoonbill" and "gorgeous flamingo." There were times, however, when the mud shoe proved of no avail, and the flat expanse remained impassable for weeks,—
"A boggy syrtis, neither sea Nor good dry land."
The coast,—directly impinged on by the drift current, and beaten by the long roll of waves which had first begun to rise under the impulsions of the trade winds on the African coast two thousand miles away,—was much exposed to tempests; and after every fresh storm from the east, a huge bank of mud used to come rolling in from the sea, three or four feet abreast, and remain wholly impassable until, during some two or three neap tides, its surface had been exposed to a tropical sun, and partially consolidated by the heat. And then the waste would become passable as before, and the chopped and broken surface, exposed to the ordinary action of the sea, and to gradual depositions during flood, would begin to be smoothed over, and the birds would find themselves no longer safe. Now, I am inclined to think that we have here the conditions necessary to the formation of the Thurso deposits. Let us suppose, near where Thurso now stands, a wide tract of flat mud banks in a sea so shallow as to be laid dry at ebb for miles together. Let us further suppose periods of tranquil deposition or re-arrangement, during which one ripple-marked stratum is laid quietly down over another, and the fish, killed by accident, or left stranded by the evaporation of the little pools, are covered up, like the plants in a botanist's drying-book, in a state of complete entireness. Let us yet further suppose great mud banks driven by occasional tempests from the deeper water beyond, and so heaped up over these sedimentary beds as to be exposed during even the flood of neap tides to the desiccating influences of the atmosphere and the sun, until the surface has become hard as a sun-burned brick, and has chopped into polygonal partings, with wide rents between. And finally, let us suppose the whole in this state laid under water at the return of stream tides, and exposed to the ordinary sedimentary action. Does it not seem probable that the alternating beds in all their conditions would be given us by such a process? In the stratum represented by the mud bank, the stone would be of what I have termed a felted, not a fissile character; its organic remains would exist in a fragmentary and scattered state,—for, torn up from their places of original deposition, and rolled onwards in the storm-impelled mud, they could not fail to be broken up and dispersed; and further, they would be in large part those of bulky deep-sea fishes. And lastly, the surface of these beds would be polygonally cracked and flawed, and the wider cracks filled up by the substance of the overlying strata. And these overlying strata, on the other hand,—the result of a period of quiet deposition in shallow water,—would be regularly bedded, and their ichthyic remains, consisting mainly of small littoral fishes, would be preserved in a state of comparative entireness. For, however, such numerous repetitions of alternately felted and fissile ripple-marked strata as we find in the neighborhood of Thurso,—repetitions carried on for hundreds of feet in vertical extent,—we require yet another condition,—that condition of gradual subsidence in the general crust which can alone account for the fact so often pressed upon the geologist in exploring the Coal Measures, that in deposits thousands of feet in thickness, each stratum in succession had been laid down in a shallow sea.]
It is a curious circumstance, that the Old Red flagstones which lie along the southern flanks of the Grampians, and are represented by the gray stone known in commerce as the Arbroath Pavement, have not, so far as is yet known, an organism in common with the Old Red flagstones of the north. I at one time supposed that the rectilinear, smooth-stemmed fucoid, already described, occurred in both series, as the gray stones have also their smooth-stemmed, rectilinear, tape-like organism; but the points of resemblance were too few and simple to justify the conclusion that they were identical, and I have since ascertained that they were entirely different plants. The fucoid of the Caithness flagstones threw off, as I have shown, in the alternate order, numerous ribbon-like branches or fronds; whereas the ribbon-like fronds or branches of the Forfarshire plant rose by dozens from a common root, like the fronds of Zostera, and somewhat resembled a scourge of cords fastened to a handle. Contemporary with this organism of the gray flagstone formation, and thickly occupying the planes on which it rests, there occur fragments of twisted stems, some of them from three to four inches in diameter (though represented by but mere films of carbonaceous matter), and irregularly streaked, or rather wrinkled, longitudinally, like the bark of some of our forest trees, though on a smaller scale. With these we find in considerable abundance irregularly-shaped patches, also of carbonaceous matter, reticulated into the semblance of polygonal, or, in some instances, egg-shaped meshes, and which remind one of pieces of ill woven lace. When first laid open, these meshes are filled each with a carbonaceous speck; and, from their supposed resemblance, in the aggregated form, to the eggs of the frog in their albuminous envelop, the quarriers term them "puddock [frog] spawn." The slabs in which they occur, thickly covered over with their vegetable impressions, did certainly remind me, when I first examined them some fifteen years ago, of the bottom of some stagnant ditch beside some decaying hedge, as it appears in middle spring, when paved with fragments of dead branches and withered grass, and mottled with its life-impregnated patches of the gelid substance regarding which a provincial poet tells his readers, in classical Scotch, that
"Puddock-spue is fu' o' e'en, An' every e'e 's a pu-head."
Higher authorities than the quarriers,—among the rest, the late Dr. Mantell,—have been disposed to regard these polygonal markings as the fossilized spawn of ancient Batrachians; but there now seems to be evidence enough from which to conclude that they are the remains, not of the eggs of an animal, but of the seed of a plant. Such was the view taken many years ago by Dr. Fleming,—the original discoverer, let me add, of fossils both in those Upper and Middle Old Red Sandstone deposits that lie in Scotland to the south of the Grampians. "These organisms," we find him saying, in a paper published in "Cheek's Edinburgh Journal" (1831), "occur in the form of circular flat patches, not equalling an inch in diameter, and composed of numerous smaller contiguous pieces. They are not unlike what might be expected to result from a compressed berry, such as the bramble or the rasp. As, however, they are found adjacent to the narrow leaves of gramineous [looking] vegetables, and chiefly in clay slate, originally lacustrine silt, it is probable that they constituted the conglobate panicles of extinct species of the genus Junicus or Sparzanium." From specimens subsequently found by Dr. Fleming, and on which he has erected his species Parka decipiens, it seems evident that the nearly circular bodies (which in all the better preserved instances circumscribe the small polygonal ones) were set in receptacles somewhat resembling the receptacle or calyx of the strawberry or rasp. Judging from one of the specimens, this calyx appears to have consisted of five pieces, which united in a central stem, and were traversed by broad irregularly diverging striae. And the spawn-like patches of Carmylie appear to be simply ill preserved specimens of this fruit, whatever its true character, in which the minute circular portions, divested of the receptacle and stem, had been thrown into irregular forms by the joint agency of pressure and decay. The great abundance of these organisms,—for so abundant are they, that visitors to the Carmylie quarries find they can carry away with them as many specimens as they please,—may be regarded as of itself indicative of a vegetable origin. It is not in the least strange, however, that they should have been taken for patches of spawn. The large-grained spawn of fishes, such as the lump-fish, salmon, or sturgeon, might be readily enough mistaken, in even the recent state, for the detached spherical-seed vessels of fruit, such as the bramble-berry, the stone-bramble, or the rasp. "Hang it!" I once heard a countryman exclaim, on helping himself at table to a spoonful of Caviare, which he had mistaken for a sweet-meat, and instantly, according to Milton, "with sputtering noise rejected,"—"Hang it for nasty stuff!—I took it for bramble berry jam."
Along with these curious remains Dr. Fleming found an organism which in form somewhat resembles the spike of one of the grasses, save that the better preserved bracts terminate in fan or kidney-shaped leaflets, with a simple venation radiating from the base. It is probably a fern, more minute in its pinnules than even our smallest specimens of true maidenhair. Its stipes, however, seems proportionally stouter than that of any of the smaller ferns with which I am acquainted. But the state of keeping of the specimen is not good, nor do I know that another has yet been found. Further, in the same beds Dr. Fleming found a curious nondescript vegetable, or rather part of a vegetable, with smooth narrow stems, resembling those of the smooth-stemmed organism of the Caithness flagstones, but unlike it in the circumstance that its detached nearly parallel stalks anastomose with each other by means of cross branches, that unite them in the middle, somewhat in the style of the Siamese twins. I have heard the doctor suggest, but know not whether he has placed the remark on record, that these parallel stems may have been but the internal fibres of some larger plant, whose more succulent portions have disappeared; and certainly, while such instances of anastomosis are rare among the stems of plants, they are common enough among their internal fibres, as all who have examined the macerated debris of a kitchen-garden or a turnip-field must have had occasion to remark. We sometimes, however, find cases of anastomosis among the stems of even the higher plants. I have seen oftener than once, in neglected hawthorn hedges, the branch of one plant entering into the stem of another, and becoming incorporated with its substance; and we are told by Professor Balfour, that this kind of chance adhesion is often seen in the branches of the ivy; and that not unfrequently, by a similar process, the roots of contiguous trees are united. Nor does it seem improbable, that what occasionally takes place among the higher plants of the present time may have been common among some of the comparatively low plants of so ancient a period as that of the Middle Old Red Sandstone. This formation of the gray tilestones has furnished one vegetable organism apparently higher in the scale than those just described, in a well marked Lepidodendron, which exhibits, like the Araucarian of the Lower Old Red, though less distinctly, the internal structure. It was found about sixteen years ago in a pavement quarry near Clockbriggs,—the last station on the Aberdeen and Forfar Railway as the traveller approaches the town of Forfar from the north. I owe my specimen of this ancient Lepidodendron to Mr. William Miller, banker, Dundee, an accomplished geologist, who has taken no little trouble in determining its true history. He has ascertained that it occurred deep in the rock, seventy-one feet from the surface; that the beds which rested over it were composed, in the descending order, first, of a conglomerate thirty feet thick; secondly, of a red rock four feet thick; thirdly, of twenty-eight feet of the soft shaly substance known to the quarriers as caulm; and fourthly, of more than nine feet of gray pavement, immediately under which, in a soft, argillaceous stratum, lay the organism. It was about four feet in length, bulged out at the lower end into a bulb-like protuberance, which may have been, however, merely an accidental result of its state of keeping; and threw off, at an acute angle, two branches about a foot from the top. It was covered with a bark of brittle coal, which is, however, wanting in all the fragments that have been preserved; and was resolved internally into a brown calcareous substance of about the hardness of ordinary marble, and very much resembling that into which the petrifactive agencies have consolidated the fossil trees of Granton and Craigleith. From the decorticated condition of the surviving fragments, and the imperfect preservation of the interior structure, in all save the central portions of its transverse sections, it yields no specific marks by which to distinguish it; but enough remains in its irregular network of cells, devoid of linear arrangement, and untraversed by medullary rays, to demonstrate its generic standing as a Lepidodendron.
[It has been questioned whether the lower place in the Old Red System should be assigned to the flagstones of Caithness and Ross, with their characteristic Dipterus and Coccosteus beds, or to the gray tilestones of Forfar and Kincardineshires, with their equally characteristic Cephalaspis. The evidence on the point is certainly not so conclusive as I deemed it fifteen years ago, when our highest authority on the subject not only regarded the tilestone of the Silurian regions of England as a member of the Old Red Sandstone (an arrangement which I am still disposed to deem the true one), but also held further, that there had been detected in this formation near Downtown Castle, Herefordshire, broken remains of Dipterus macrolepidotus, one of the best marked ichthyolites of the flagstones of Caithness and Orkney. A great and unbroken series of fossiliferous rocks, with Dipterus at its base, Cephalaspis in its medial spaces, and Holoptychius at its top, might well be regarded as the analogue of the Old Red of Scotland, with the Caithness flagstones ranged at its bottom, the Cephalaspis beds of Forfarshire placed in its middle, and the Holoptychius beds of Scot-Crag and Clashbinnie on its upper horizon; but since that time the tilestones have been transferred to the Upper Silurian division of rocks, and the evidence furnished by their supposed Dipterus has not been confirmed. And as the Old Red Sandstones of Scotland have no true fossiliferous base, but rest on primary rocks both to the south and north of the Grampians, it may be regarded as in some degree a moot point whether the lowest fossiliferous beds to the north be older or newer than those to the south, or, what is quite possible, of the same age. Provisionally, however, I have arranged my paper on the supposition that the Coccostean formation of the north is the lowest and oldest of the three; and this from the following considerations. In the first place, the Coccosteus and its contemporaries appear in the north at a very short distance above the base of the system. I have disinterred an Osteolepis from a fish bed near Cromarty only thirty-three feet over the great conglomerate, and only a hundred and twenty-nine feet over the granitic gneiss beneath; whereas the Cephalaspis beds occur high above the primary base of the system in the south,—at some distance over even the thick conglomerate of Stonehaven and Dunnottar; and under this conglomerate, as shown in the section furnished by the valley of the North Esk, there lies a pale red sandstone member of the system, estimated by Colonel Imrie at seven hundred and eighty feet in thickness. The conglomerate itself he estimates at twelve hundred feet. Adopting as correct Colonel Imrie's section, taken along the banks of the North Esk,—and the colonel was unquestionably a truthful observer,—the Cephalaspis beds of the south lie nearly two thousand (nineteen hundred and eighty) feet above the Azoic slates on which the Old Red Sandstone of Forfarshire rests, whereas the Coccosteus and Osteolepis beds of the north lie only one hundred and twenty-nine feet over the Azoic gneiss on which the Old Red Sandstone of Cromarty rests. There is thus at least room in the south for an underlying fossiliferous formation between that of the Cephalaspis and the base of the system, but none in the north beneath that of the Coccosteus and its base. In the north we find the room lying above, between the Coccostean and Holoptychian formations, and represented by that great unfossiliferous deposit of pale sandstone to which the hills of Hoy and the rocks of Duncansbay Head and of Tarbet Ness belong. Further, in the second place, while the upper or Holoptychian formation is found directly overlying that of the Coccosteus in only one locality,—Moray,—we find it directly overlying that of the Cephalaspis in two widely separated localities;—in the vast band of Old Red which runs diagonally across the island from sea to sea, parallel to the Grampian chain, and in the immensely developed Red Sandstones of England and Wales. And it is of course more probable that the two corroborative instances should represent the natural succession of the formations, and the single instance the accidental gap in the scale consequent on the missing formation, than that, vice versa, the solitary instance should represent the natural succession, while the two mutually corroborative ones should represent, in localities widely apart, the mere accident of the gap. But, in the third place, I attach more weight to a conclusion founded on the positive character of the groups of organic remains by which the three great formations of the Old Red System are characterized, than I do to either of these considerations. The organisms of the Cephalaspian deposits differ generically, and in their whole aspect, from both those of the Coccostean and Holoptychian formations; whereas the organisms of the Coccostean formations, while they resemble generically and in the group those of the Holoptychian one, mainly differ from them specifically. The extreme generic difference in the one case argues evidently a great difference in condition,—the lesser specific difference in the other, a great difference in point of time. The Cephalaspian formation might, as a fresh water formation, be nearly contemporary with either of the other two, or, as seems more probable, interposed between them; while they themselves, on the other hand, generically similar and decidedly marine in their character, must have been so widely separated in time, that all the species of the lower group became extinct ere those of the upper one had been ushered into being. And such are some of the considerations that still lead me, notwithstanding the failure of previous evidence, to hold, at least, provisionally, that our Scottish flagstones to the north of the Grampians occupy a lower horizon than our Scottish tilestones to the south. It must, however, be stated, on the other hand, that the crustaceans of the gray tilestones of Forfar and Kincardine not a little resemble those of the Upper Silurian and red tilestone beds of England; and that, judging from the ichthyodorulites found in both, their fishes must have been at least generically allied. The crustaceans of the upper Silurian of Lesmahagow, too, seem certainly much akin to those of the Forfarshire tilestones.]
Above this gray tilestone formation lies the Upper Old Red Sandstone, with its peculiar group of ichthyic organisms, none of which seem specially identical with those of either the Caithness or the Forfarshire beds. For it is an interesting circumstance, suggestive surely of the vast periods which must have elapsed during its deposition, that the great Old Red System has, as I have just said, its three distinct platforms of organic existence, each wholly different from the others. Generically and in the group, however, the Upper fishes much more closely resemble, I repeat, the fishes of the Lower or Caithness and Cromarty platform, than they do those of the Forfarshire and Kincardine one. The vegetable remains of the Upper formation in Scotland are both rare and ill preserved. I have seen what I deemed fucoidal markings dimly impressed on the planes of some of the strata, not in the carbonaceous form so common in the other two formations, but as mere colored films of a deeper red than the surrounding matrix. Further, I have detected in the same beds, and existing in the same state, fragments of a striated organism, which may have formed part of either a true calamite, like those of the Coal Measures, or of some such striated but jointless vegetable as that of the Lower Old Red of Thurso and Lerwick. With these markings ferns are occasionally found; and to one of these, from the light which it throws on the true place in the scale of a series of deposits in a sister country, there attaches no little interest. I owe my specimen to Mr. John Stewart of Edinburgh, who laid it open in a micaceous red sandstone in the quarry of Prestonhaugh, near Dunse, where it is associated with some of the better known ichthyic organisms of the Upper Old Red Sandstone, such as Pterichthys major and Holoptychius Nobilissimus. Existing as but a deep red film in the rock, with a tolerably well defined outline, but without trace of the characteristic venation on which the fossil botanist, in dealing with the ferns, founds his generic distinctions, I could only determine that it was either a Cyclopterus or Neuropterus. My collection was visited, however, by the late lamented Edward Forbes, only a few weeks before his death; and he at once recognized in my Berwickshire fern, so unequivocally an organism of the Upper Old Red, the Cyclopterus Hibernicus of those largely developed beds of yellow sandstone which form so marked a feature in the geology of the south of Ireland, and whose true place, whether as Upper Old Red or Lower Carboniferous, has been the subject of so much controversy. I had been previously introduced by Professor Forbes, in the Museum of Economic Geology in Jermyn Street, London, to an interesting collection of plants from these yellow beds, and had an opportunity afforded me of examining the only ichthyic organism hitherto found associated with them; and was struck, though I could not identify its species, with its peculiarly Old Red aspect; but the evidence of the Cyclopterus is of course more conclusive than that of the fish; and we may, I think, legitimately conclude, that in Ireland, as in our own country, it was a contemporary of the great Pterichthys (P. major),—the hugest, and at least one of the last, of his race,—and gave its rich green to the hill sides of what is still the Emerald Island during the latter ages of the Old Red Sandstone, and ere the Carboniferous period had yet begun. The Cyclopterus Hibernicus, as shown both by the Prestonhaugh specimen and those of Ireland, was a bipinnate fern of very considerable size,—probably a tree fern. Its pinnae, opposite in the lower part of the frond, are alternate in the upper; while its leaflets, which are of a sub-rhomboidal form, and so closely ranged as to impinge on each other, are at least generally alternate in their arrangement throughout. Among living plants it seems most nearly represented by a South American species,—Didymocloena pulcherrima,—one of the smaller tree ferns. The leaves of this graceful species are bipinnate, like those of the fossil; and the pinnae (thickly set with simple, alternately arranged leaflets) are opposite in the lower part of the frond, and alternate in the upper. Widely as they are separated in time, the recent South American Didymocloena and the Old Red Sandstone Cyclopterus, that passed into extinction ere the times of the Coal, might be ranged together, so far at least as appears from their forms, as kindred species. It were very desirable that we had a good monograph of the Irish Old Red plants, the contemporaries of the latter, as the completest and best preserved representatives of the Middle Palaeozoic flora yet found. Sir Roderick Murchison has figured a single pinnae of this Cyclopterus in his recently published "Siluria;" and Sir Charles Lyell, both that and one of its contemporary Lepidodendra, in the last edition of his "Elements." These interesting fragments, however, serve but to excite our curiosity for more. When urging Professor Edward Forbes on the subject, ere parting from him for, alas! what proved to be the last time, he intimated an intention of soon taking it up; but I fear his purposed monograph represents only one of many works, important to science, which his untimely death has arrested for mayhap long years to come.
In the uppermost beds of the Upper Old Red formation in Scotland, which are usually of a pale or light yellow color, the vegetable remains again become strongly carbonaceous, but their state of preservation continues bad,—too bad to admit of the determination of either species or genera; and not until we rise a very little beyond the system do we find the remains of a flora either rich or well preserved. But very remarkable is the change which at this stage at once occurs. We pass at a single stride from great poverty to great wealth. The suddenness of the change seems suited to remind one of that experienced by the voyager, when,—after traversing for many days some wide expanse of ocean, unvaried save by its banks of floating sea weed, or, where occasionally and at wide intervals, he picks up some leaf-bearing bough, or marks some fragment of drift weed go floating past,—he enters at length the sheltered lagoon of some coral island, and sees all around the deep green of a tropical vegetation descending in tangled luxuriance to the water's edge,—tall, erect ferns, and creeping lycopodiaceae, and the pandanus, with its aerial roots and its screw-like clusters of narrow leaves, and, high over all, tall palms, with their huge pinnate fronds, and their curiously aggregated groups of massive fruit. And yet the more meagre vegetation of the earlier time is not without its special interest. The land plants of the Old Red Sandstone seem to compose, all over the world, the most ancient of the terrestrial floras. It was held only a few years ago, that the Silurians of the United States had their plants allied to the Lepidodendron. But the group in which these occur has since been transferred from the Upper Silurian to the Old Red System; and we find it expressly stated by Professor H. D. Rogers, in his valuable contribution to the "Physical Atlas" (second edition, 1856), that "the Cadent [or Lower Old Red] strata are the oldest American formations in which remains of a true terrestrial vegetation have yet been discovered." It has been shown, too, by Sir Roderick Murchison, that the supposed Silurian plants of Oporto are in reality Carboniferous, and owe their apparent position to a reverse folding of the strata. I have already referred to the solitary spore-cases of the Ludlow Rocks; and beneath these rocks, says Sir Roderick (1854), "no remains of plants have been discovered which are recognizably of terrestrial origin." Scanty, too, as the terrestrial flora of the Old Red Sandstone everywhere is, we find it exhibiting very definitely the leading Palaeozoic features. Its prevailing plants are the ferns and their apparent allies. It has in our own country, as has been just shown, its ferns, its lepidodendra, its striated plants allied to the calamites, and its decided araucanite; in America, in the Cadent series, it had its "plants allied to ferns and lepidodendra;" and in the Devonian basin of Sabero in Spain, its characteristic organisms are, a lepidodendron (L. Chemungensis), and a very peculiar fern (Sphenopteris laxus). But while in its main features it resembled the succeeding flora of the Carboniferous period, it seems in all its forms to have been specifically distinct. It was the independent flora of an earlier creation than that to which we owe the coal. For the meagreness of the paper in which I have attempted to describe it as it occurs in Scotland, I have but one apology to offer. My lecture contains but little; but then, such is the scantiness of the materials on which I had to work, that it could not have contained much: if, according to the dramatist, the "amount be beggarly," it is because the "boxes are empty." Partly, apparently, from the circumstance that the organisms of this flora were ill suited for preservation in the rocks, and partly because, judging from what appears, the most ancient lands of the globe were widely scattered and of narrow extent, this oldest of the floras is everywhere the most meagre.
ON THE LESS KNOWN FOSSIL FLORAS OF SCOTLAND.
In the noble flora of the Coal Measures much still remains to be done in Scotland. Our Lower Carboniferous rocks are of immense development; the Limestones of Burdiehouse, with their numerous terrestrial plants, occur many hundred feet beneath our Mountain Limestones; and our list of vegetable species peculiar to these lower deposits is still very incomplete. Even in those higher Carboniferous rocks with which the many coal workings of the country have rendered us comparatively familiar, there appears to be still a good deal of the new and the unknown to repay the labor of future exploration. It was only last year that Mr. Gourlay of this city (Glasgow) added to our fossil flora a new Volkmannia from the coal field of Carluke; and I detected very recently in a neighboring locality (the Airdrie coal field), though in but an indifferent state of keeping, what seems to be a new and very peculiar fern. It presents at first sight more the appearance of a Cycadaceous frond than any other vegetable organism of the Carboniferous age which I have yet seen. From a mid stem there proceed at right angles, and in alternate order, a series of sessile, lanceolate, acute leaflets, nearly two inches in length by about an eighth part of an inch in breadth, and about three lines apart. Each is furnished with a slender midrib; and, what seems a singular, though not entirely unique, feature in a fern, their edges are densely hirsute, and bristle with thick, short hair, nearly as stiff as prickles. The venation is not distinctly preserved; but enough remains to show that it must have been peculiar,—apparently radiating outwards from a series of centres ranged along the midrib. Nay, the apparent hairs seem to be but prolongations of the nerves carried beyond the edges of the leaflets. There is a Stigmaria, too, on the table, very ornate in its sculpture, of which I have now found three specimens in a quarry of the Lower Coal Measures near Portobello, that has still to be figured and described. In this richly ornamented Stigmaria the characteristic areolae present the ordinary aspect. Each, however, forms the centre of a sculptured star, consisting of from eighteen to twenty rays, or rather the centre of a sculptured flower of the composite order, resembling a meadow daisy or sea-aster. The minute petals,—if we are to accept the latter comparison,—are of an irregularly lenticular form, generally entire, but in some instances ranged in two, or even three, concentric lines round the depressed centre of the areolae; while the interspaces outside are occupied by numerous fretted markings, resembling broken fragments of petals, which, though less regularly ranged than the others, are effective in imparting a richly ornate aspect to the whole.
Ever since the appearance, in 1846, of Mr. Binney's paper on the relations of stigmaria to sigillaria as roots and stems, I have been looking for distinguishing specific marks among the former; and, failing for a time to find any, I concluded that, though the stems of the sigillarian genus were variously sculptured, their roots might in all the species have been the same. The present rich specimen does seem, however, to bear the specific stamp; and, from the peculiar character of the termination of another specimen on the table, I am inclined to hold that the stigmaria may have borne the appearance rather of underground stems than of proper roots. This specimen suddenly terminates, at a thickness of two and a half inches, in a rounded point, abrupt as that of one of the massier cacti; and every part of the blunt sudden termination is thickly fretted over with the characteristic areolae. The slim tubular rootlets must have stuck out on every side from the obtuse rounded termination of this underground stem, as we see, on a small scale, the leaflets of our larger club mosses sticking out from what are comparatively the scarce less abrupt terminations of their creeping stems and branches. In at least certain stages of growth the sub-aerial stems of Lepidodendron also terminated abruptly (see Fig. 24); and the only terminal point of Ulodendron I ever saw was nearly as obtuse as that of Stigmaria.
I have been long desirous of acquainting myself with the true character of this latter plant (Ulodendron), but hitherto my labors have not been very successful. A specimen of Ulodendron minus, however, now on the table, which I disinterred several years ago from out a bed of ferruginous shale in the Water of Leith, a little above the village of Colinton, exhibits several peculiarities which, so far as I know, have not yet been described. Though rather less than ten inches in length by about three inches in breadth, it exhibits no fewer than seven of those round, beautifully sculptured scars, ranged rectilinearly along the trunk, by which this ancient genus is so remarkably characterized. It is covered with small, sharply relieved, obovate scales, most of them furnished with an apparent midrib, and with their edges slightly turned up; from which peculiarities, and their great beauty, they seem suited to remind the architect of that style of sculpture adopted by Palladio from his master Vitruvius, when, in ornamenting the Corinthian and composite torus, lie fretted it into closely imbricated obovate leaves. These scales are ranged in elegant curves, not unlike those ornamental curves,—a feat of the turning-lathe,—which one sees roughening the backs of ladies' watches of French manufacture. My fossil exhibited, as it lay in the rock, what I never saw in any other specimen,—a true branch sticking out at an acute angle from the stem, and fretted with scales of a peculiar form, which in one little corner appear also on the main stem, but which differ so considerably from those of the obovate, apparently imbricated type, that, if found on a separate specimen, they might be held to indicate difference of species. It has been shown by Messrs. Lindley and Hutton, on the evidence of one of the specimens figured in the "Fossil Flora," that the line of circular scars so remarkable in this genus, and which is held to be the impressions made by a rectilinear range of almost sessile cones, existed in duplicate on each stem,—a row occurring on two of the sides of the plant directly opposite each other. The branch in my specimen struck off from one of the intermediate sides at right angles with the cones. We already know that these were ranged in one plane; nor, if the branches were ranged in one plane also,—certainly the disposition of branch which would consort best with such a disposition of cone,—would the arrangement be without example in the vegetable kingdom as it even now exists. "Our host," says the late Captain Basil Hall, in his brief description of the island of Java, "carried us to see a singular tree, which had been brought from Madagascar, called familiarly the Traveller's Friend, Urania being, I believe, its botanic name. We found it to differ from most other trees in having all its branches in one plane, like the sticks of a fan or the feathers of a peacock's tail." I may further mention, that the specimen which showed me the abrupt cactus-like terminations of Ulodendron repeated the evidence of Messrs. Lindley and Hutton's specimen regarding the arrangement of the cone scars on opposite sides, and showed also that these scars ascended to within little more than an inch of the top of the plant.
As there are cases in which the position of a fossil plant may add, from its bearing on geologic history, a threefold interest to the fossil itself, regarded simply as an organism, I may be permitted to refer to a circumstance already recorded, that there was a well marked Bechera detected about two years ago by Dr. Macbean of Edinburgh, an accomplished naturalist and careful observer, in a thin argillaceous stratum, interposed, in the Queen's Park, between a bed of columnar basalt and a bed of trap-tuff, in the side of the eminence occupied atop by the ruins of St. Anthony's Chapel. The stratified bed in which it occurs seems, from its texture and color, to be composed mainly of trappean materials, but deposited and arranged in water; and abounds in carbonaceous markings, usually in so imperfect a state of keeping that, though long known to some of the Edinburgh geologists, not a single species, or even genus, were they able to determine. All that could be said was, that they seemed fucoidal, and might of course belong to any age. The Bechera, however, shows that the deposit is one of the Lower Coal Measures. There was found associated with it a tooth of a Carboniferous Holoptychius, whose evidence bore out the same conclusion; and both fossils derive an importance from the light which they throw on the age of the bed of tuff which underlies the stratum in which they occur. At least this trap-rock must be as old as the fossiliferous layer which rests upon it, or rather, as shown by its underlying position, a little older: it must be a trap of the earlier Carboniferous period. Further, it must have been, not injected among the strata, but poured out over the surface,—in all probability covered at the time by water; and there must have formed over it, ere another overflow of trap took place, a thin sedimentary bed charged with fragments of the plants of the period, and visited, when in the course of deposition, by some of its fishes.
Even among the vegetable organisms of our Coal Measures, already partially described and figured, much remains to be accomplished in the way of restoration. Portions of Sphenopteris bifida, for instance, a fern of the Lower Carboniferous rocks have been repeatedly figured; but a beautiful specimen on the table, which exhibits what seems to be the complete frond of the plant, will give, I doubt not, fresh ideas respecting the general framework, if I may so speak, of this skeleton fern, to even those best acquainted with the figures; and an elaborate restoration of its contemporary, Sphenopteris affinis (see frontispiece) which I completed from a fine series of specimens in my collection, will be new, as a whole, to those most familiar with this commonest of the Burdiehouse fossils. From comparisons instituted between minute portions of this Sphenopteris and a recent fern, it has been held considerably to resemble a Davallia of the West Indies; whereas it will be seen from the entire frond that it was characterized by very striking peculiarities, exemplified, say some of our higher botanical authorities, to whom I have submitted my restoration, by no fern that now lives. The frond of Davallia Canariensis, though unlike in its venation, greatly resembles in general outline one of the larger pinnae of Sphenopteris affinis; but these pinnae form only a small part of the entire frond of this Sphenopteris. It was furnished with a stout leafless rachis, or leaf-stalk, exceedingly similar in form to that of our common brake (Pteris aquilina). So completely, indeed, did it exhibit the same club-like, slightly bent termination, the same gradual diminution in thickness, and the same smooth surface, that one accustomed to see this part of the bracken used as a thatch can scarce doubt that the stipes of Sphenopteris would have served the purpose equally well; nay, that were it still in existence to be so employed, a roof thatched with it, on which the pinnae and leaflets were concealed, and only the club-like stems exposed, row above row, in the style of the fern-thatcher, could not be distinguished, so far as form and size went, from a roof thatched with brake. High above the club-like termination of the rachis the stem divided into two parts, each of which, a little higher up, also divided into two; these in turn, in at least the larger fronds, also bifurcated; and this law of bifurcation,—a marked, mayhap unique, peculiarity in a fern,—regulated all the larger divisions of the frond, though its smaller pinnae and leaflets were alternate. It was a further peculiarity of the plant that, unlike the brake, it threw off, ere the main divisions of its rachis took place, two pinnae placed in the alternate order, and of comparatively small size. The frond of Sphenopteris bifida was of a more simple form than that of its larger congener, and not a little resembled a living fern of New Zealand, Coenopteris vivipara. It was tripinnate; its secondary stems were placed directly opposite on the midrib, but its tertiary ones in the alternate arrangement; and its leaflets which were also alternate, were as rectilinear and slim as mere veins, or as the thread-like leaflets of asparagus. Like the fronds of Coenopteris when not in seed, it must have presented the appearance of the mere macerated framework of a fern. I need scarce remark that, independently of the scientific interest which must attach to restorations of these early plants, they speak powerfully to the imagination, and supply it with materials from which to construct the vanished landscapes of the Carboniferous ages. From one such restored fern as the two now submitted to the Association, it is not difficult to pass in fancy to the dank slopes of the ancient land of the Lower Coal Measures, when they waved as thickly with graceful Sphenopteres as our existing hill sides with the common brake; and when every breeze that rustled through the old forests bent in mimic waves their slim flexible stems and light and graceful foliage.
In 1844, when Professor Nicol, of Marischal College, Aberdeen, appended to his interesting "Guide to the Geology of Scotland," a list of the Scottish fossils known at the time, he enumerated only two vegetable species of the Scotch Oolitic system,—Equisetum columnare and Pinites or Peuce Eiggensis; the former one of the early discoveries of our distinguished President, Sir Roderick Murchison; the latter, of the late Mr. William Nicol of Edinburgh. Chiefly from researches in the Lias of Eathie, near Cromarty, and in the Oolites of Sutherland and the Hebrides, I have been enabled to increase the list from two to rather more than fifty species,—not a great number, certainly, regarded as the sole representative of a flora; and yet it may be deemed comparatively not a very small one by such as may remember, that in 1837, when Dr. Buckland published the second edition of his "Bridgewater Treatise," Adolphe Brogniart had enumerated only seventy species of plants as occurring in all the Secondary formations of Europe, from the Chalk to the Trias inclusive. In a paper such as the present I can of course do little more than just indicate a few of the more striking features of the Scottish flora of the middle Secondary ages. Like that of the period of the true Coal, it had its numerous coniferous trees. As shown by the fossil woods of Helmsdale and Eigg, old Oolitic Scotland, like the Scotland of three centuries ago, must have had its mighty forests of pine; and in one respect these trees seem to have more nearly resembled those of the recent pine forests of our country than the trees of the coniferous forests of the remote Carboniferous era. For while we scarce ever find a cone associated with the coniferous woods of the Coal Measures,—Lindley and Hatton never saw but one from all the English coal fields, and Mr. Alexander Bryson of Edinburgh, only one from all the coal fields of Scotland,—tree-cones of at least four different species, more probably of five, are not rare in our Scottish deposits of the Lias and Oolite. It seems not improbable that in the Carboniferous genera Pinites, Pitus, and Anabathra, which approach but remotely to aught that now exists, the place of the ligneous scaly cone may have been taken, as in the junipers and the yews, by a perishable berry; while the Pines and Araucarians of the Oolite were, like their congeners in recent times, in reality coniferous, that is, cone-bearing trees. It is another characteristic of these Secondary conifers, that while the woods of the Palaeozoic periods exhibit often, like those of the tropics, none of the dense concentric lines of annual growth which mark the reign of winter, these annual lines are scarce less strongly impressed on the Oolitic woods than on those of Norway or of our own country in the present day. In some of the fossil trees these yearly rings are of great breadth; they seem to have sprung up in the rich soil of sheltered hollows and plains, and to have increased in diameter from half an inch to three quarters of an inch yearly; while in other trees of the same species the yearly zones of growth are singularly narrow,—in some instances little more than half a line in thickness. Rooted on some exposed hill side, in a shallow and meagre soil, they increased their diameter during the twelvemonth little more than a line in the severer seasons, and little more than an eighth part of an inch even when the seasons were most favorable. Further, whether the rings be large or small, we ordinarily find them occurring in the same specimens in groups of larger and smaller. In one of my Helmsdale specimens, indicative generally of rapid growth, there are four contiguous annual rings, which measure in all an inch and two twelfths across, while the four contiguous rings immediately beside them measure only half an inch. "If, at the present day," says a distinguished fossil botanist, "a warm and moist summer produces a broader annual layer than a cold and dry one, and if fossil plants exhibit such appearances as we refer in recent plants to a diversity of summers, then it is reasonable to suppose that a similar diversity formerly prevailed." The same reasoning is of course as applicable to groups of annual layers as to single annual layers; and may we not venture to infer from the almost invariable occurrence of such groups in the woods of this ancient system, that that ill-understood law of the weather which gives us in irregular succession groups of colder and warmer seasons, and whose operation, as Bacon tells us, was first remarked in the provinces of the Netherlands, was as certainly in existence during the ages of the Oolite as at the present time?
Twigs which exhibit the foliage of these ancient conifers seem to be less rare in our Scotch deposits than in those of England of the same age. My collection contains fossil sprigs, with the slim needle-like leaves attached, of what seem to be from six to seven different species; and it is worthy of notice, that they resemble in the group rather the coniferae of the southern than those of the northern hemisphere. One sprig in my collection seems scarcely distinguishable from that of the recent Altingia excelsa; another, from that of the recent Altingia cunninghami. Lindley and Hutton figure in their fossil flora a minute branch of Dacrydium cupressinum, in order to show how nearly the twigs of a large tree, from fifty to a hundred feet high, may resemble some of the "fossils referable to Lycopodiaceae." More than one of the Oolitic twigs in my collection are of a resembling character, and may have belonged either to cone-bearing trees or to club mosses. Respecting, however, the real character of at least one of the specimens,—a minute branch from the Lias of Eathie, with the leaflets attached,—there can be no mistake. The thicker part of the stem is in such a state of keeping, that it presents to the microscope, in a sliced preparation, the internal structure, and exhibits, as in recent coniferous twigs of a year's growth, a central pith, a single ring of reticulated tissue arranged in lines that radiate outwards, and a thin layer of enveloping bark. Nothing, then, can be more certain than that this ancient twig, which must be accepted as representative of the foliage of whole forests of the Secondary ages in Scotland, formed part of a conifer of the Lias; and the foliage of several of the other twigs, its contemporaries, though I have failed to demonstrate their true character in the same way, bear a scarce less coniferous aspect. The cones of the period, from the circumstance that they are locked up in a hard limestone that clings closely around their scales, and from the further circumstance that the semi-calcareous lignite into which they are resolved is softer and less tenacious than the enclosing matrix, present, when laid open, not their outer surfaces, but mere sections of their interior; and give, in consequence, save in their general proportions and outline, but few specific marks by which to distinguish them. We see, however, in some cases in these sections what would be otherwise unseen,—the flat naked seeds lying embedded in their hollow receptacles between the scales, and in as perfect a state of keeping as the seeds of recent pines that had ripened only a twelvemonth ago. Had not the vitality of seeds its limits in time, like life of all other kinds, one might commit these perfect fossil germs to the soil, in the hope of seeing the old extinct forests called, through their agency, a second time into existence. Of three apparent species of cones which occur in the Eathie Lias, the smallest seems to have resembled in size and appearance that of the Scotch fir; the largest, which consisted from bottom to top, as seen in section, of from nine to ten scales, appears to have been more in the proportions of the oblong oval cones of the spruce family; while a cone of intermediate length, but of considerably greater breadth, assumed the rounded form of the cones of the cedar. I have found in the same deposit what seems to be the sprig of a conifer, with four apparently embryo cones attached to it in the alternate order. These are rather more sessile than the young cones of the larch; but the aspect of the whole is that of a larch twig in early summer, when the minute and tender cones, possessed of all the beauty of flowers, first appear along its sides.
Among conifers of the Pine and Araucarian type we mark the first appearance in this system, in at least Scotland, of the genus Thuja. One of the Helmsdale plants of this genus closely resembles the common Arbor Vitae (Thuja occidentalis) of our gardens and shrubberies. It exhibits the same numerous slim, thick-clustered branchlets, covered over by the same minute, sessile, scale-like leaves; and so entirely reminds one of the recent Thuja, that it seems difficult to conceive of it as the member of a flora so ancient as that of the Oolite. But not a few of the Oolitic plants in Scotland bear this modern aspect. The great development of its Cycadaceae,—an order unknown in our Coal Measures,—also forms a prominent feature of the Oolitic flora. One of the first known genera of this curious order,—the genus Pterophyllum,—appears in the Trias. It distinctively marks the commencement of the Secondary flora, and intimates that the once great Palaeozoic flora, after gradually waning throughout the Permian ages, and becoming extinct at their close, had been succeeded by a vegetation altogether new. At least one of the Helmsdale forms of this family is identical with a Yorkshire species already named and figured,—Zamia pectinata: a well marked Zamia which occurs in the Lias of Eathie appears to be new. Its pinnate leaves were furnished with a strong woody midrib, so well preserved in the rock, that it yields its internal structure to the microscope. The ribbon-like pinnae or leaflets were rectilinear, retaining their full breadth until they united to the stem at right angles, but set somewhat awry; and, like several of the recent Zamiae, they were striped longitudinally with cord-like lines. (Fig. 133.) Even the mode of decay of this Zamia, as shown by the abrupt termination of its leaflets, exactly resembled that of its existing congeners. (Fig. 134.) The withered points of the pinnae of recent Zamiae drop off as if clipped across with a pair of scissors; and in fossil fronds of this Zamia of the Lias we find exactly the same clipped-like appearance. (Fig. 135.) Another Scotch Zamia (Fig. 136), which occurs in the Lower Oolite of Helmsdale, resembles the Eathie one in the breadth of its leaflets, but they are not wholly so rectilinear, diminishing slightly towards their base of attachment; they are ranged, too, along the stem or midrib, not at a right angle, but at an acute one; the line of attachment is not set awry, but on the general plane of the leaf; and the midrib itself is considerably less massive and round. A third species from the same locality bears a general resemblance to the latter; but the leaflets are narrower at the base, and, as the print indicates (Fig. 136), so differently attached to the stem, that from the pressure in the rock most of them have become detached; while yet a fourth species (Fig. 137), very closely resembles a Zamia of the Scarborough Oolite,—Z. lanceolata. The leaflets, however, contract much more suddenly from their greatest breadth than those of lanceolata, into a pseudo-footstalk; and the contraction takes place not almost equally on both sides, as in that species, but almost exclusively on the upper side. And so, provisionally at least, this Helmsdale Zamia may be regarded as specifically new.
With the leaves of the Eathie Zamia, we find, in this northern outlier of the Lias, cones of a peculiar form, which, like the leaves themselves, are still unfigured and undescribed, and some of which could scarce have belonged to any coniferous tree. In one of these (Fig. 138), the ligneous bracts or scales, narrow and long, and gradually tapering till they assume nearly the awl-shaped form, cluster out thick from the base and middle portions of the cone, and, like the involucral appendages of the hazel-nut, or the sepals of the yet unfolded rose-bud, sweep gracefully upwards to the top, where they present at their margins minute denticulations. In another species the bracts are broader, thinner, and more leaf-like: they rise, too, more from the base of the cone, and less from its middle portions; so that the whole must have resembled an enormous bud, with strong woody scales, some of which extended from base to apex. The first described of these two species seems to have been more decidedly a cone than the other; but it is probable that they were both connecting links between such leathern seed-bearing flowers as we find developed in Cycas revoluta, and such seed-bearing cones as we find exemplified in Zamia pungens. The bud-like cone, however, does not seem to have been that of a Cycadaceous plant, as it occupied evidently not a terminal position on the plant that bore it, like the cones of Zamia or the flowers of Cycas, but a lateral one, like the lateral flowers of some of the Cactus tribe. Another class of vegetable forms, of occasional occurrence in the Helmsdale beds, seems intermediate between the Cycadaceae and the ferns: at least, so near is the approach to the ordinary fern outline, while retaining the stiff ligneous character of Zamia, that it is scarce less difficult to determine to which of the two orders of plants such organisms belonged, than to decide whether some of the slim graceful sprigs of foliage that occur in the rocks beside them belonged to the conifers or the club mosses. And I am informed by Sir Charles Lyell, that (as some of the existing conifers bear a foliage scarce distinguishable from that of Lycopodiaceae), so a recently discovered Zamia is furnished with fronds that scarce differ from those of a fern. Even Zamia pectinata may, as Sternberg remarks, have been a fern. Lindley and Hutton place it merely provisionally among the Cycadaceae, in deference to the judgment of Adolphe Brogniart, and point out its resemblance to Polypodium pectinatum; and a small Helmsdale frond which I have placed beside it bears the impress of a character scarce less equivocal. The flora of the Oolite was peculiarly a flora of intermediate forms.
We recognize another characteristic of our Oolitic flora in its simple-leaved fronds, in some of the species not a little resembling those of the recent Scolopendrium, or Hart's-Tongue fern,—a form regarded by Adolphe Brogniart as peculiarly characteristic of his third period of vegetation. These simple ferns are, in the Helmsdale deposits, of three distinct types. There is first a lanceolate leaf, from two and a half to three inches in length, of not unfrequent occurrence, which may have formed, however, only one of the four leaflets, united by their pseudo-footstalks, which compose the frond of Glossopteris,—a distinctive Oolitic genus. There is next a simple ovate lanceolate leaf, from four to five and a half inches in length, which in form and venation, and all save its thrice greater size, not a little resembles the leaflets of a Coal Measure neuropteris,—N. acuminata. And, in the third place, there are the simple leaves that in general outline resemble, as I have said, the fronds of the recent Hart's-Tongue fern (Scolopendrium vulgare), except that their base is lanceolate, not cordate. Of these last there are two kinds in the beds, representative of two several species, or, as their difference in general aspect and detail is very great, mayhap two several genera. The smaller of the two has a slender midrib, depressed on its upper side, and flanked on each side by a row of minute, slightly elongated protuberances, but elevated on the under side, and flanked by rows of small but well marked grooves, that curve outwards to the edges of the leaf. The larger resemble a Taeniopteris of the English and Continental Oolites, save that its midrib is more massive, its venation less at right angles with the stem, its base more elongated, and its size much greater. Some of the Helmsdale specimens are of gigantic proportions. From, however, a description and figure of a plant of evidently the same genus,—a Taeniopteris of the Virginian Oolite, given by Professor W.B. Rogers of the United States,—I find that some of the American fronds are larger still. My largest leaf from Helmsdale must have been nearly five inches in breadth; and if its proportions were those of some of the smaller ones of apparently the same species from the same locality, it must have measured about thirty inches in length. But fragments of American leaves have been found more than six inches in breadth, and whose length cannot have fallen short of forty inches. The Taeniopteris, as its name bears, is regarded as a fern. From, however, the leathern-like thickness of some of the Sutherland specimens,—from the great massiveness of their midrib,—from the rectilinear simplicity of their fibres,—and, withal, from, in some instances, their great size,—I am much disposed to believe that in our Scotch, mayhap also in the American species, it may have been the frond of some simple-leaved Cycas or Zamia. But the point is one which it must be left for the future satisfactorily to settle; though provisionally I may be permitted to regard these leaves as belonging to some Cycadaceous plant, whose fronds, in their venation and form, resembled the simple fronds of Scolopendrium, just as the leaves of some of its congeners resembled the fronds of the pinnate ferns.
I have already referred to the close resemblance which certain Cycadaceous genera bear to certain of the fern family. In at least two species of Pterophyllum,—P. comptum and P. minus,—the divisions of the leaflets seem little else than accidental rents in a simple frond; in P. Nelsoni they are apparently nothing more; and similar divisions, evidently, however, the effect of accident, and less rounded at their extremities than in at least P. comptum, we find exhibited by some of the Helmsdale specimens of Taeniopteris (See Fig. 142, p. 488.) But whatever the nature of these simple fronds, they seem to impart much of its peculiar character, all the world over, to the flora of the Oolitic ages.
The compound ferns of the formation are numerous, and at least proportionally a considerable part of them seem identical in species with those of the Oolite of England. (See Fig. 143.) Among these there occur Pecopteris Whitbiensis, Pecopteris obtusifolia, Pecopteris insignis,—all well marked English species; with several others. It has, besides, its apparent ferns, that seem to be new—(Fig. 144)—that are at least not figured in any of the fossil floras to which I have access,—(Fig. 145),—such as a well defined Pachypteris, with leaflets broader and rounder than the typical P. lanceolata, and a much stouter midrib; a minute Sphenopteris too, and what seems to be a Phlebopteris, somewhat resembling P. propinqua, but greatly more massive in its general proportions. The equisetacea we find represented in the Brora deposits by Equisetum columnare,—a plant the broken remains of which occur in great abundance, and which, as was remarked by our President many years ago, in his paper on the Sutherlandshire Oolite, must have entered largely into the composition of the bed of lignite known as the Brora Coal. We find associated with it what seems to be the last of the Calamites,—Calamites arenaceus,—a name, however, which seems to have been bestowed both on this Oolitic plant and a resembling Carboniferous species. The deposit has also its Lycopodites, though, from their resemblance in foliage to the conifers, there exists that difficulty in drawing the line between them to which I have already adverted. One of these, however, so exactly resembles a lycopodite of both the Virginian and Yorkshire Oolite,—L. uncifolius,—that I cannot avoid regarding it as specifically identical; and it seems more than doubtful whether the stem which I have placed among the conifers is not a lycopodite also. It exhibits not only the general outline of the true club moss, but, like the fossil club mosses too, it wants that degree of ligniferous body in the rock which the coniferous fossils almost always possess. Yet another of the organisms of the deposit seems to have been either a lycopodite or a fern. Its leaflets are exceedingly minute, and set alternately on a stem slender as a hair,—circumstances in which it resembles some of the tiny lycopodites of the tropics, such as Lycopodium apodium. I must mention, however, that the larger plant of the same beds which I have placed beside it, and which resembles it so closely that my engraver finds it difficult to indicate any other difference between them than that of size, appears to be a true fern, not a lycopodium. To yet another vegetable organism of the system,—an organism which must be regarded, if I do not mistake its character, as at once very interesting and extraordinary, occurring as it does so low in the scale, and bearing an antiquity so high,—I shall advert, after a preliminary remark on a general characteristic of the flora to which it belongs, but to which it seems to furnish a striking exception.
From the disappearance of many of those anomalous types of the Coal Measures which so puzzle the botanist, and the extensive introduction of types that still exist, we can better conceive of the general features and relations of the flora of the Oolite than of those of the earlier floras. And yet the general result at which we arrive may be found not without its bearing on the older vegetations also. Throughout almost all the families of this Oolitic flora, there seems to have run a curious bond of relationship, which, like those ties which bound together some of the old clans of our country, united them, high and low, into one great sept, and conferred upon them a certain wonderful unity of character and appearance. Let us assume the ferns as our central group. Though less abundant than in the earlier creation of the Carboniferous system, they seem to have occupied, judging from their remains, very considerable space in the Oolitic vegetation; and with the ferns there were associated in great abundance the two prevailing families of the Pterides,—Equiseta and Lycopodia,—plants which, in most of our modern treatises on the ferns proper, take their place as the fern allies. (See Fig. 148.) Let us place these along two of the sides of a pentagon,—the Lycopodia on the right side of the ferns, the Equiseta on the left; further, let us occupy the two remaining sides of the figure by the Coniferae and the Cycadaceae,—placing the Coniferae on the side next the Lycopodia, and the Cycadaceae, as the last added keystone of the erection, between these and the Equiseta. And now, let us consider how very curious the links are which give a wonderful unity to the whole. We still find great difficulty in distinguishing between the foliage of some of even the existing club mosses and the conifers; and the ancient Lepidodendra are very generally recognized as of a type intermediate between the two. Similar intermediate types, exemplified by extinct families, united the conifers and the ferns. The analogy of Kirchneria with the Thinnfeldia, says Dr. Braun, is very remarkable, notwithstanding that the former is a fern, and that the latter is ranked among conifers. The points of resemblance borne by the conifers to the huge Equiseta of the Oolitic period seem to have been equally striking. The pores which traverse longitudinally the channelled grooves by which the stems of our recent Equiseta are so delicately fluted, are said considerably more to resemble the discs of pines and araucarians than ordinary stomata. Mr. Francis does not hesitate to say, in his work on British Ferns, that the relation of this special family to the Coniferae is so strong, both in external and internal structure, that it is not without some hesitation he places them among the fern allies; and it has been ascertained by Mr. Dawes, in his researches regarding the calamite, that in its internal structure this apparent representative of Equiseta in the earlier ages of the world united "a network of quadrangular tissue similar to that of Coniferae to other quadrangular cells arranged in perpendicular series," like the cells of plants of a humbler order. The relations of the Cycadacean order to ferns on the one hand, and to the Coniferae on the other, are equally well marked. As in the ferns, the venation of its fronds is circinate, or scroll-like,—they have in several respects a resembling structure,—in at least one recent species they have a nearly identical form; and fronds of this fern-like type seem to have been comparatively common during the times of the Oolite. On the other hand, the Cycadaceae manifest close relations to the conifers. Both have their seeds originally naked; both are cone-bearing; both possess discs on the sides of their cellules; and in both, in the transverse section, these cellules are subhexagonal, and radiate from a centre. Such were the very curious relations that united into one great sept the prevailing members of the Oolitic flora; and similar bonds of connection seem to have existed in the floras of the still earlier ages.
In the Oolite of Scotland I have, however, at length found trace of a vegetable organism that seems to have lain, if I may so express myself, outside the pentagon, and was not a member of any of the great families which it comprised. (See Fig. 151.) I succeeded about four years ago in disinterring from the limestone of Helmsdale what appears to be a true dicotyledonous leaf, with the fragment of another leaf, which I at first supposed might have belonged to a plant of the same great class, but which I now find might have been a portion of a fern. When Phlebopteris Phillipsii was first detected in the Oolite of Yorkshire, Lindley and Hatton, regarding it as dicotyledonous, originated their term Dictyophillum as a general one for all such leaves. But it has since been assigned to a greatly lower order,—the ferns; and Sir Charles Lyell has kindly shown me that an exotic fern of the present day exhibits exactly such a reticulated style of venation as my Helmsdale fragment. (See Fig. 152, p. 497.) The other leaf, however, though also fragmentary, and but indifferently preserved, seems to be decidedly marked by the dicotyledonous character; and so I continue to regard it, provisionally at least, as one of the first precursors in Scotland of our great forest trees, and of so many of our flowering and fruit-bearing plants, and as apparently occupying the same relative place in advance of its contemporaries as that occupied by the conifer of the Old Red Sandstone in advance of the ferns and Lycopodaceae with which I found it associated. In the arrangement of its larger veins the better preserved Oolitic leaf somewhat resembles that of the buckthorn; but its state of keeping is such that it has failed to leave its exterior outline in the stone.
One or two general remarks, in conclusion, on the Oolite flora of Scotland may be permitted me by the Association. In its aspect as a whole it greatly resembles the Oolite flora of Virginia, though separated in space from the locality in which the latter occurs by a distance of nearly four thousand miles. There are several species of plants common to both, such as Equisetum columnare, Calamites arenaceus, Pecopteris Whitbiensis, Lycopodites uncifolius, and apparently Taeniopteris magnifolia; both, too, manifest the great abundance in which they were developed of old by the beds of coal into which their remains have been converted. The coal of the Virginia Oolite has been profitably wrought for many years: it is stated by Sir Charles Lyell, who carefully examined the deposit, and has given as the results of his observation in his second series of Travels in the United States, that the annual quantity taken from the Oolitic pits by Philadelphia alone amounted to ten thousand tons; and though, on the other hand, the Sutherlandshire deposit has never been profitably wrought, it has been at least wrought more extensively than any other in the British Oolite. The seam of Brora, varying from three feet three to three feet eight inches in thickness, furnished, says Sir Roderick Murchison, between the years 1814 and 1826, no less than seventy thousand tons of coal. Such is its extent, too, that nearly thirty miles from the pit's mouth (in Ross-shire under the Northern Sutor) I have found it still existing, though in diminished proportions, as a decided coal seam, which it must have taken no small amount of vegetable matter to form. And almost on the other side of the world, nearly five thousand miles from the Sutherland beds, and more than eight thousand miles from the Carolina ones, the same Oolitic flora again appears, associated with beds of coal. At Nagpur in Central India the Oolitic Sandstones abound in simple fronded ferns, such us Taeniopteris and Glossopteris, and has its Zamites, its coniferous leaves, and its equisetaceae.
Compared with existing floras, that of our Scottish Oolite seems to have most nearly resembled the flora of New Zealand,—a flora remarkable for the great abundance of its ferns, and its vast forests of coniferous trees, that retain at all seasons their coverings of acicular spiky leaves. It is to this flora that Dacrydium cupressinum,—so like a club moss in its foliage,—belongs; and Podocarpus ferrugineus,—a tree which more closely resembles in its foliage the Eathie conifer, save that its spiky leaves are somewhat narrower and longer than any other with which I am acquainted. About two thirds of the plants which cover the plains, or rise on the hill-sides of that country, are cryptogamic, consisting mainly of ferns and their allies; and it is a curious circumstance,—which was, however, not without precedent in the merely physical conditions of the Oolitic flora of Scotland,—that so shallow is the soil even where its greatest forests have sprung up, and so immediately does the rock lie below, that the central axes of the trees do not elongate downwards into a tap, but throw out horizontally on every side a thick network of roots, which rises so high over the surface as to render walking through the woods a difficult and very fatiguing exercise. The flora of the Oolite, like that of New Zealand, seems to have been in large part cryptogamic, consisting of ferns and the allied horse-tail and club moss families. Its forests seem to have contained only cone-bearing trees; at least among the many thousand specimens of its fossil woods which have been examined, no tissue of the true, dicotyledonous character has yet been found; and with the exception of the leaves just described, all those yet found in the System, which could have belonged to true trees, are of the acicular form common to the Coniferae, and show in their dense ligneous structure that they were persistent, not deciduous. Nor is there evidence wanting that many of the Coniferae of the period grew in so shallow a soil, that their tap-roots were flattened and bent backwards, and they were left to derive their sole support, like the trees of the New Zealand forests, from such of their roots as shot out horizontally. We even know the nature of the rock upon which they rested. As shown by fragments still locked up among the interstices of their petrified roots, it was an Old Red flagstone similar to that of Caithness in the neighborhood of Wick and Thurso, and containing the same fossil remains. In the water-rolled pebbles of the Conglomerate of Helmsdale and Port Gower,—pebbles encrusted by Oolitic corals, and enclosed in a calcareous paste, containing Oolitic belemnites and astreae,—I have found the well marked fishes and fucoids of the Old Red Sandstone. As shown by the appearance of the rounded masses in which these lay, they must have presented as ancient an appearance in the times of the Lower Oolite as they do now; and the glimpse which they lent of so remote an antiquity, through the medium of an antiquity which, save for the comparison which they furnished the means of instituting, might be well deemed superlatively remote, I have felt singularly awe-inspiring and impressive. Macaulay anticipates a time when the traveller from some distant land shall take his stand on a broken arch of London Bridge to survey the ruins of St. Paul's. In disinterring from amid the antique remains of the Oolite the immensely more antique remains of the Old Red Sandstone, I have felt as such a traveller would feel if, on setting himself to dig among the scattered heaps for memorials of the ruined city, he had fallen on what had been once the Assyrian Gallery of the British Museum, and had found mingling with the antiquities of perished London the greatly older and more venerable antiquities of Nineveh or of Babylon. The land of the Oolite in this northern locality must have been covered by a soil which,—except that from a lack of the boulder clays it must have been poorer and shallower,—must have not a little resembled that of the lower plains of Cromarty, Caithness, and Eastern Ross. And on this Palaeozoic platform, long exposed, as the Oolitic Conglomerates abundantly testify, to denuding and disintegrating agencies,—a platform beaten by the surf where it descended to the sea level, and washed in the interior by rivers, with here a tall hill or abrupt precipice, and there a flat plain or sluggish morass,—there grew vast forests of cone-bearing trees, tangled thickets of gigantic equisetaceae, numerous forms of Cycas and Zamia, and wide-rolling seas of fern, amid whose open spaces club mosses of extinct tribes sent forth their long, creeping stems, spiky and dry, and thickly mottled with pseudo-spore-bearing catkins.
The curtain drops over this ancient flora of the Oolite in Scotland; and when, long after, there is a corner of the thick enveloping screen withdrawn, and we catch a partial glimpse of one of the old Tertiary forests of our country, all is new. Trees of the high dicotyledonous class, allied to the plane and the buckthorn, prevail in the landscape, intermingled, however, with dingy funereal yews; and the ferns and equisetae that rise in the darker openings of the wood approach to the existing type. And yet, though eons of the past eternity have elapsed since we looked out upon Cycas and Zamia, and the last of the Calamites, the time is still early, and long ages must lapse ere man shall arise out of the dust, to keep and to dress fields waving with the productions of yet another and different flora, and to busy himself with all the labor which he taketh under the sun. Our country, in this Tertiary time, has still its great outbursts of molten matter, that bury in fiery deluges many feet in depth, and many square miles in extent, the debris of wide tracts of woodland and marsh; and the basaltic columns still form in its great lava bed; and ever and anon, as the volcanic agencies awake, clouds of ashes darken the heavens, and cover up the landscape as if with accumulated drifts of a protracted snow storm. Who shall declare what, throughout those long ages, the history of creation has been? We see at wide intervals the mere fragments of successive floras; but know not how what seem the blank interspaces were filled, or how, as extinction overtook in succession one tribe of existences after another, and species, like individuals, yielded to the great law of death, yet other species were brought to the birth, and ushered upon the scene, and the chain of being was maintained unbroken. We see only detached bits of that green web which has covered our earth ever since the dry land first appeared; but the web itself seems to have been continuous throughout all time; though ever as breadth after breadth issued from the creative loom, the pattern has altered, and the sculpturesque and graceful forms that illustrated its first beginnings and its middle spaces have yielded to flowers of richer color and blow, and fruits of fairer shade and outline; and for gigantic club mosses stretching forth their hirsute arms, goodly trees of the Lord have expanded their great boughs; and for the barren fern and the calamite, clustering in thickets beside the waters, or spreading on flowerless hill slopes, luxuriant orchards have yielded their ruddy flush, and rich harvests their golden gleam.
 The Prayer will be found at the end of these Memorials.
 The same revolver proved to be the instrument of death to another person, two days after. The circumstances are thus related in the Edinburgh Witness of December 27:—
"A most melancholy event, arising out of the following circumstances, occurred yesterday in the shop of Mr. Thomson, gunmaker. In the beginning of July, last year, Mr. Hugh Miller bought a six-shot revolving chamber pistol, size of ball ninety-two to the pound, from the late firm of Messrs. Alexander Thomson & Son, gunmakers, 16 Union Place. A few days after, he called and said he thought it a little stiff in its workings, and got it made to revolve more readily. The pistol has not been seen by Mr. Thomson since then; but in his absence a few minutes at dinner yesterday, Professor Miller called about twenty minutes from two, and asked Mr. Thomson's foreman how many of the six shots had been fired. He added, 'Mind, it is loaded.' The foreman, instead of removing the breech or chamber to examine it, bad incautiously turned the pistol entire towards his own person, and lifting up the hammer with his fingers, while he counted the remaining loaded chambers, he must have slipped his fingers while the pistol was turned to his own head. It exploded, and the ball lodging in the angle of his right eye, he fell back a lifeless corpse. The pistol is a bolted one, which permits of being carried loaded with perfect safety. Having been wet internally, rust may have stopped the action of the bolt. It is a singular fact that Hugh Miller dropped the pistol into the bath, where it remained for several hours. This may account for the apparent incaution of Mr. Thomson's foreman."
 See ante, p. 9.
 The horizontal lines in this diagram indicate the divisions of the various geologic systems; the vertical lines the sweep of the various classes or sub-classes of plants across the geologic scale, with, so far as has yet been ascertained, the place of their first appearance in creation; while the double line of type below shows in what degree the order of their occurrence agrees with the arrangement of the botanist. The single point of difference indicated by the diagram between the order of occurrence and that of arrangement, viz., the transposition of the gymnogenous and monocotyledonous classes, must be regarded as purely provisional. It is definitely ascertained that the Lower Old Red Sandstone has its coniferous wood, but not yet definitely ascertained that it has its true monocotyledonous plants; though indications are not awanting that the latter were introduced upon the scene at least as early as the pines or araucarians; and the chance discovery of some fossil in a sufficiently good state of keeping to determine the point may, of course, at once retranspose the transposition, and bring into complete correspondence the geologic and botanic arrangements.