Lecture First The Palæontological History of Plants
Palæontology, or the science of ancient organisms, deals, as its subject, with all the plants and animals of all the geologic periods. It bears nearly the same sort of relation to the physical history of the past, that biography does to the civil and political history of the past. For just as a complete biographic system would include every name known to the historian, a complete palæontologic system would include every fossil known to the geologist. It enumerates and describes all the organic existences of all the extinct creations,—all the existences, too, of the present creation that occur in the fossil or semi-fossil form; and, thus coextensive in space with the earth’s surface,—nay, greatly more than coextensive with the earth’s surface,—for in the vast hieroglyphic record which our globe composes, page lies beneath page, and inscription covers over inscription,—coextensive, too, in time, with every period in the terrestrial history since being first began upon our planet,—it presents to the student a theme so vast and multifarious, that it might seem but the result, on his part, of a proper modesty, conscious of the limited range of his powers, and of the brief and fleeting term of his life, were he to despair of being ever able effectually to grapple with it. “But,” to borrow from one of the most ingenious of our Scottish metaphysicians, “in this, as in other instances in which nature has given us difficulties with which to cope, she has not left us to be wholly overcome.” “If,” says Dr. Thomas Brown, in his remarks on the classifying principle,—“if she has placed us in a labyrinth, she has at the same time furnished us with a clue which may guide us, not, indeed, through all its dark and intricate windings, but through those broad paths which conduct us into day. The single power by which we discover resemblance or relation in general, is a sufficient aid to us in the perplexity or confusion of our first attempts at arrangement. It begins by converting thousands, and more than thousands, into one; and, reducing in the same manner the numbers thus formed, it arrives at last at the few distinctive characters of those great comprehensive tribes on which it ceases to operate, because there is nothing left to oppress the memory or the understanding.”
But, is this all? Can the Palæontologist but say that that classifying principle, which in every other department of science yields such assistance to the memory, is also of use in his, or but urge that it enables him to sort and arrange his facts; and that, by converting one idea into the type and exemplar of many resembling ones, it imparts to him an ability of carrying not inadequate conceptions of the mighty whole in his mind? If this were all, you might well ask, Why obtrude upon us, in connection with your special science, a common semi-metaphysical idea, equally applicable to all the sciences,—in especial, for example, to that botany which is the science of existing plants, and to that zoology which is the science of existing animals? Nay, I reply, but it is not all. I refer to this classifying principle because, while it exists in relation to all other sciences as a principle—to use the words of the metaphysician just quoted—“given to us by nature,”—as a principle of the mind within,—it exists in Palæontological science as a principle of nature itself,—as a principle palpably external to the mind. It is a marvellous fact, whose full meaning we can as yet but imperfectly comprehend, that myriads of ages ere there existed a human mind, well nigh the same principles of classification now developed by man’s intellect in our better treatises of zoology and botany, were developed on this earth by the successive geologic periods; and that the by-past productions of our planet, animal and vegetable, were chronologically arranged in its history, according to the same laws of thought which impart regularity and order to the works of the later naturalist and phytologists.
I need scarce say how slow and interrupted in both provinces the course of arrangement has been, or how often succeeding writers have had to undo what their predecessors had done, only to have their own classifications set aside by their successors in turn. At length, however, when the work appears to be well nigh completed, a new science has arisen, which presents us with a very wonderful means of testing it. Cowley, in his too eulogistic ode to Hobbes,—smit by the singular ingenuity of the philosophic infidel, and unable to look through his sophisms to the consequences which they involved,—could say, in addressing him, that
“only God could know
Whether the fair idea he did show
Agreed entirely with God’s own or no.”
And he then not very wisely added,—
“This, I dare boldly tell,
’T is so like truth, ’t will serve our turn as well.”
We now know, however, that no mere resemblance to truth will for any considerable length of time serve its turn. It is because the resemblances have, like those of Hobbes, been mere resemblances, that so much time and labor have had to be wasted by the pioneers of science in their removal; and, now that a wonderful opportunity has occurred of comparing, in this matter of classification, the human with the Divine idea,—the idea embodied by the zoologists and botanists in their respective systems, with the idea embodied by the Creator of all in geologic history,—we cannot perhaps do better, in entering upon our subject, than to glance briefly at the great features in which God’s order of classification, as developed in Palæontology, agrees with the order in which man has at length learned to range the living productions, plant and animal, by which he is surrounded, and of which he himself forms the most remarkable portion. In an age in which a class of writers not without their influence in the world of letters would fain repudiate every argument derived from design, and denounce all who hold with Paley and Chalmers as anthropomorphists, that labor to create for themselves a god of their own type and form, it may be not altogether unprofitable to contemplate the wonderful parallelism which exists between the Divine and human systems of classification, and—remembering that the geologists who have discovered the one had no hand in assisting the naturalists and phytologists who framed the other—soberly to inquire whether we have not a new argument in the fact for an identity in constitution and quality of the Divine and human minds,—not a mere fanciful identity, the result of a disposition on the part of man to imagine to himself a God bearing his own likeness, but an identity real and actual, and the result of that creative act by which God formed man in his own image.
The study of plants and animals seems to have been a favorite one with thoughtful men in every age of the world. According to the Psalmist, these great “works of the Lord are sought out of all them that have pleasure therein.” The Book of Job, probably the oldest writing in existence, is full of vivid descriptions of the wild denizens of the flood and desert; and it is expressly recorded of the wise old king, that he “spake of trees, from the cedar tree that is in Lebanon, even unto the hyssop that springeth out of the wall; and also of beasts, and of fowl, and of creeping things, and of fishes.” Solomon was a zoologist and botanist; and there is palpable classification in the manner in which his studies are described. It is a law of the human mind, as has been already said, that, wherever a large stock of facts are acquired, the classifying principle steps in to arrange them. “Even the rudest wanderer in the fields,” says Dr. Brown, “finds that the profusion of blossoms around him—in the greater number of which he is able himself to discover many striking resemblances—may be reduced to some order of arrangement.” But, for many centuries, this arranging faculty labored but to little purpose. As specimens of the strange classification that continued to obtain down till comparatively modern times, let us select that of two works which, from the literary celebrity of their authors, still possess a classical standing in letters,—Cowley’s “Treatise on Plants,” and Goldsmith’s “History of the Earth and Animated Nature.” The plants we find arranged by the poet on the simple but very inadequate principle of size and show. Herbs are placed first, as lowest and least conspicuous in the scale; then flowers; and, finally, trees. Among the herbs, at least two of the ferns—the true maidenhair and the spleenwort—are assigned places among plants of such high standing as sage, mint, and rosemary: among the flowers, monocotyledons, such as the iris, the tulip, and the lily, appear among dicotyledons, such as the rose, the violet, the sunflower, and the auricula: and among trees we find the palms placed between the plum and the olive; and the yew, the fir, and the juniper, flanked on one side by the box and the holly, and on the other by the oak. Such, in treating of plants, was the classification adopted by one of the most learned of English poets in the year 1657.
Nor was Goldsmith,-who wrote more than a century later, much more fortunate in dealing with the animal kingdom. Buffon had already published his great work; and even he could bethink him of no better mode of dividing his animals than into wild and tame. And in Goldsmith, who adopted, in treating of the mammals, a similar principle, we find the fishes and molluscs placed, in advance of the sauroid, ophidian, and batrachian reptiles,—the whale united in close relationship to the sharks and rays,—animals of the tortoise kind classed among animals of the lobster kind, and both among shell fish, such as the snail, the nautilus, and the oyster. And yet Goldsmith was engaged on his work little more than eighty years ago. In fine, the true principles of classification in the animal kingdom are of well nigh as recent development as geologic science itself, and not greatly more ancient in even the vegetable kingdom. It would, of course, be wholly out of place to attempt giving a minute history here of the progress of arrangement in either department; but it can scarce be held that the natural system of plants was other than very incomplete previous to 1789, when Jussieu first enunciated his scheme of classification; nor did it receive its later improvements until so late as 1846, when, after the publication, in succession, of the schemes of De Candolle and Endlicher, Lindley communicated his finished system to the world. And there certainly existed no even tolerably perfect system of zoology until 1816, when the “Animal Kingdom” of Cuvier appeared. Later naturalists,—such as Agassiz, in his own special department, the history of fishes, and Professor Owen in the invertebrate divisions,—have improved on the classification of even the great Frenchman; but for purposes of comparison between the scheme developed in geologic history and that at length elaborated by the human mind, the system of Cuvier will be found, for at least our present purpose, sufficiently complete. And in tracing through time the course of the vegetable kingdom, let us adopt, as our standard to measure it by, the system of Lindley.
Commencing at the bottom of the scale, we find the Thallogens, or flowerless plants which lack proper stems and leaves,—a class which includes all the algæ. Next succeed the Acrogens, or flowerless plants that possess both stems and leaves,—such as the ferns and their allies. Next, omitting an inconspicuous class, represented by but a few parasitical plants incapable of preservation as fossils, come the Endogens,—monocotyledonous flowering plants, that include the palms, the liliaceæ, and several other families, all characterized by the parallel venation of their leaves. Next, omitting another inconspicuous tribe, there follows a very important class,—the Gymnogens,—polycotyledonous trees, represented by the conifers; and cycadaceæ. And, last of all, come the Dicotyledonous Exogens,—a class to which all our fruit, and what are known as our “forest trees,” belong, with a vastly preponderating majority of the herbs and flowers that impart fertility and beauty to our gardens and meadows. This last class, though but one, now occupies much greater space in the vegetable kingdom than all the others united.
Such is the arrangement of Lindley, or rather an arrangement the slow growth of ages, to which this distinguished botanist has given the last finishing touches. And let us now mark how closely it resembles the geologic arrangement as developed in the successive stages of the earth’s history.
The most ancient period of whose organisms any trace remains in the rocks seems to have been, prevailingly at least, a period of Thallogens. We must, of course, take into account the fact, that it has yielded no land plants, and that the sea is everywhere now, as of old, the great habitat of the algæ,—one of the four great orders into which the Thallogens are divided. There appear no traces of a terrestrial vegetation until we reach the uppermost beds of the Upper Silurian System. But, account for the fact as we may, it is at least worthy of notice, that, alike in the systems of our botanists and in the chronological arrangements of our geologists, the first or introductory class which occurs in the ascending order is this humble Thallogenic class. There is some trace in the Lower Silurians of Scotland of a vegetable structure which may have belonged to one of the humbler Endogens, of which, at least, a single genus, the Zosteraceæ, still exists in salt water; but the trace is faint and doubtful, and, even were it established, it would form merely a solitary exception to the general evidence that the first known period of vegetable existence was a period of Thallogens. The terrestrial remains of the Upper Silurians of England, the oldest yet known, consist chiefly of spore-like bodies, which belonged, says Dr. Hooker, to Lycopodiaceæ,—an order of the second or acrogenic class. And, in the second great geologic period,—that of the Old Red Sandstone,—we find this second class not inadequately represented. In its lowest fossiliferous beds we detect a Lycopodite which not a little resembles one of the commonest of our club mosses,—Lycopodium clavatum,—with a minute fern and a large striated plant resembling a calamite, and evidently allied to an existing genus of Acrogens, the equisetaceæ. In the Middle Old Red Sandstone there also occurs a small fern, with some trace of a larger; and one of its best preserved vegetable organisms is a lepidodendron,—an extinct ally of the Lycopodiums; while in the upper beds of the system, especially as developed in the south of Ireland, the noble fern known as Cyclopteris Hibernicus is very abundant. This fern has been detected also in the Upper Old Red of our own country, mingled with fragments of contemporary calamites. With, however, these earliest plants of the land yet known, there occurs a true wood, which belonged, as shown by its structure, to a gymnospermous or polycotyledonous tree, and which we find associated with remains of Coccosteus and Diplacanthus.
And here let me remark, that the facts of Palæontological science compel us to blend, in some degree, with the classification of our modern botanists, that of the botanists of an earlier time. In a passage already quoted, Solomon is said to have discoursed of plants, “from the cedar tree that is in Lebanon, to the hyssop that springeth out of the wall,”—from the great tree to the minute herb; and Cowley rose, in his metrical treatise, as has been shown, from descriptions of herbs and flowers to descriptions of fruit and forest trees. And as in every age in which there existed a terrestrial vegetation there seem to have been “trees” as certainly as “herbs,” the palæontological botantist finds that he has, in consequence, to range his classes, not in one series, but in two,—the Gymnogens, or cone-bearing trees, in a line nearly parallel with the Acrogens, or flowerless, spore-bearing herbs. But the arrangement is in no degree the less striking from the circumstance that it is ranged, not in one, but in two lines. It is, however, an untoward arrangement for the purposes of the Lamarckian, whose peculiar hypothesis would imperatively demand, not a double, but a single column, in which the ferns and club mosses would stand far in advance, in point of time, of the Coniferæ. In the Coal Measures, so remarkable for the great luxuriance of their flora, both the Gymnogens and Acrogens are largely developed, with a very puzzling intermediate class, that, while they attained to the size of trees, like the former, retained in a remarkable degree, as in the Lepidodendra and the Calamites, the peculiar features of the latter. And with these there appear, though more sparingly, the Endogens,—monocotyledonous plants, represented by a few palm-like trees (Palmacites), a few date-like fruits (Trigonocarpum), and a few grass-like herbs (Poacites). In the great Secondary division, the true dicotyledonous plants first appear; but, so far as is yet known, no dicotyledonous wood. In the earlier formations of the division a degree of doubt attaches to even the few leaves of this class hitherto detected; but in the Lower Cretaceous strata they become at once unequivocal in their character, and comparatively abundant, both as individuals and species; and in the Tertiary deposits they greatly outnumber all the humbler classes, and appear not only as herbs, but also as great trees. Not, however, until shortly before the introduction of man do some of their highest orders, such as the Rosaceæ, come upon the scene, as plants of that great garden—including the fields of the agriculturist—which it has been part of man’s set task upon earth to keep and to dress. And such seems to be the order of classification in the vegetable kingdom, as developed in creation, and determined by the geologic periods.
The parallelism which exists between the course of creation, as exhibited in the animal kingdom, and the classification of the greatest zoologist of modern times, is perhaps still more remarkable. Cuvier divides all animals into vertebrate and invertebrate; the invertebrates consisting, according to his arrangement, of three great divisions,—mollusca, articulata, and radiata; and the vertebrates, of four great classes,—the mammals, the birds, the reptiles, and the fishes. From the lowest zone at which organic remains occur, up till the higher beds of the Lower Silurian System, all the animal remains yet found belong to the invertebrate divisions. The numerous tables of stone which compose the leaves of this first and earliest of the geologic volumes correspond in their contents with that concluding volume of Cuvier’s great work in which he deals with the mollusca, articulata, and radiata; with, however, this difference, that the three great divisions, instead of occurring in a continnous series, are ranged, like the terrestrial herbs and trees, in parallel columns. The chain of animal being on its first appearance is, if I may so express myself, a threefold chain;—a fact nicely correspondent with the further fact, that we cannot in the present creation range serially, as either higher or lower in the scale, at least two of these divisions,—the mollusca and articulata. In one of the higher beds of the Upper Silurian System,—a bed which borders on the base of the Old Red Sandstone,—the vertebrates make their earliest appearance in their fourth or ichthyic class; and we find ourselves in that volume of the geologic record which corresponds to Cuvier’s volume on the fishes. In the many-folded pages of the Old Red Sandstone, till we reach the highest and last, there occur the remains of no other vertebrates than those of this fourth class; but in its uppermost deposits there appear traces of the third or reptilian class; and in passing upwards still, through the Carboniferous, Permian, and Triassic Systems, we find reptiles continuing the master existences of the time. The geologic volume in which these great formations are included corresponds to the Cuvierian one devoted to the Reptilia. Early in the Oolitic System, birds, Cuvier’s second class of the vertebrata, make their first appearance, though their remains, like those of birds in the present time, are rare and infrequent; and, for at least the earlier periods of their existence, we know that they were,—that they haunted for food the waters of the period, and waded in their shallows,—only from marks similar to those by which Crusoe became first aware of the visits paid to his island by his savage neighbors,—their footprints, left impressed on the sands over which they stalked of old. This early Oolitic volume corresponds in its contents to the section devoted by Cuvier, in his great work, to his second class, the birds. And in the Stonisfield slate,—a deposit interposed between the “Inferior” and “Great Oolites,” we detect the earliest indications of his first or mammaliferous class, apparently represented, however, by but one order,—the Marsupiata, or pouched animals, to whose special place in the scale I shall afterwards have occasion to refer. Not until we reach the times of the Tertiary division do the mammals in their higher orders appear. The great Tertiary volume corresponds to those volumes of Cuvier which treat of the placental animals that suckle their young. And finally,—last born of creation,—man appears upon the scene, in his several races and varieties; the sublime arch of animal being at length receives its keystone; and the finished work stands up complete, from foundation to pinnacle, at once an admirably adjusted occupant of space, and a wonderful monument of Divine arrangement and classification, as it exists in time. Save at two special points, to which I shall afterwards advert, the particular arrangement unfolded by geologic history is exactly that which the greatest and most philosophic of the naturalists had, just previous to its discovery, originated and adopted as most conformable to nature: the arrangements of geologic history as exhibited in time, if, commencing at the earliest ages, we pursue it downwards, is exactly that of the “Animal Kingdom” of Cuvier read backwards.
Let us then, in grappling with the vast multiplicity of our subject, attempt reducing and simplifying it by means of the classifying principle; not simply, however,—again to recur to the remark of the metaphysician,—as an internal principle given us by nature, but as an external principle exemplified by nature. Let us take the organisms of the old geologic periods in the order in which they occur in time; secure, as has been shown, that if our chronology be correct, our classification will, as a consequence, be good. It will be for the natural theologians of the coming age to show the bearing of this wonderful fact on the progress of man towards the just and the solid, and on the being and character of man’s Creator,—to establish, on the one hand, against the undue depreciators of intellect and its results, that in certain departments of mind, such as that which deals with the arrangement and development of the scheme of organic being, human thought is not profitlessly revolving in an idle circle, but progressing Godwards, and gradually unlocking the order of creation. And, on the other hand, it will be equally his proper business to demand of the Pantheist how,—seeing that only persons (such as the Cuviers and Lindleys) could have wrought out for themselves the real arrangement of this scheme,—how, I say, or on what principle, it is to be held that it was a scheme originated and established at the beginning, not by a personal, but by an impersonal God. But our present business is with the fact of the parallel arrangements, Divine and human,—not with the inferences legitimately deducible from it.
Beginning with the plants, let us, however, remark, that they do not precede in the order of their appearance the humbler animals. No more ancient organism than the Oldhamia of the Lowest Irish Silurians, a plant-like zoophyte somewhat resembling our modern sertularia, has yet been detected by the geologist; though only a few months ago the researches of Mr. Salter in the ancient rocks of the Longmynd, Shropshire, previously deemed unfossiliferous, have given, to it what seem to be contemporary vegetable organisms, in a few ill-preserved fucoids. So far as is yet known, plants and animals appear together. The long upward march of the animal kingdom takes its departure at its starting point from a thick forest of algæ. In Bohemia, in Norway, in Sweden, in the British Islands, in North America, wherever, in fine, what appears to be the lowest, or at least one of the lowest, zones of life has yet been detected, the rocks are found to be darkened by the remains of algæ, so abundantly developed in some cases, that they compose, as in the ancient Lower Silurians of Dumfriesshire, impure beds of anthracite several feet in thickness. Apparently, from the original looseness of their texture, the individual plants are but indifferently preserved; nor can we expect that organisms so ancient should exhibit any very close resemblance to the plants which darken the half-tide rocks and skerries of our coasts at the present time. We do detect, however, in some of these primordial fossils, at least a noticeable likeness to families familiar to the modern algæologist. The cord-like plant, Chorda filum, known to our children as “dead men’s ropes,” from its proving fatal at times to the too adventurous swimmer who gets entangled in its thick wreaths, had a Lower Silurian representative, known to the Palæontologist as the Palæochorda, or ancient chorda, which existed apparently in two species,—a larger and smaller. The still better known Chondrus crispus, the Irish moss or carrageen of our cookery-books, has likewise its apparent though more distant representative in Chondritis, a Lower Silurian algæ, of which there seems to exist at least three species. The fucoids, or kelp weeds, appear to have had also their representatives in such plants as Fucoides gracilis of the Lower Silurians of the Malverns; in short, the Thallogens of the first ages of vegetable life seem to have resembled, in the group, and in at least their more prominent features, the algæ of the existing time. And with the first indications of land we pass direct from the Thallogens to the Acrogens,—from the sea weeds to the fern allies. The Lycopodiaceæ;, or club mosses, bear in the axils of their leaves minute circular cases, which form the receptacles of their spore-like seeds. And when, high in the Upper Silurian System, and just when preparing to quit it for the Lower Old Red Sandstone, we detect our earliest terrestrial organisms, we find that they are composed exclusively of those little spore receptacles. The number of land plants gradually increases as we ascend into the overlying system. Still, however, the Flora of even the Old Red is but meagre and poor; and you will perhaps permit me to lighten this part of my subject, which threatens too palpably to partake of the poverty of that with which it deals, by a simple illustration.
We stand, at low ebb, on the outer edge of one of those iron-bound shores of the Western Highlands, rich in forests of algæ, from which, not yet a generation bygone, our Celtic proprietors used to derive a larger portion of their revenues than from their fields and moors. Rock and skerry are brown with sea weed. The long cylindrical lines of Chorda filum, many feet in length, lie aslant in the tideway; long shaggy bunches of Fucus serratus and Fucus nodosus droop heavily from the rock sides; while the flatter ledges, that form the uneven floor upon which we tread, bristle thick with the stiff, cartilaginous, many-cleft fronds of at least two species of chondrus,—the common carrageen, and the smaller species, C. Norvegicus. Now, in the thickly-spread fucoids of this Highland shore we have not a very inadequate representation of the first, or thallogenic vegetation,—that of the great Silurian period, as exhibited in the rocks, from the base to nearly the top of the system. And should we add to the rocky tract, rich in fucoids, a submarine meadow of pale shell sand, covered by a deep green swathe of zostera, with its jointed saccharine roots and slim flowers, unfurnished with petals, we would render it perhaps more adequately representative still.
We cross the beach, and enter on a bare brown moor, comparatively fertile, however, in the club mosses. One of the largest and finest of the species, Lycopodium clavatum, with its long scaly stems and upright spikes of lighter green,—altogether a graceful though flowerless plant, which the herd-boy learns to select from among its fellows, and to bind round his cap,—goes trailing on the drier spots for many feet over the soil; while at the edge of trickling runnel or marshy hollow, a smaller and less hardy species, Lycopodium inundatum, takes its place. The marshes themselves bristle thick with the deep green horse tail, Equisetum fluviatile, with its fluted stem and verticillate series of linear brandies. Two other species of the same genus, Equisetum sylvaticum and Equisetum arvense, flourish on the drier parts of the moor, blent with two species of minute ferns, the moonwort and the adder’s tongue,—ferns that, like the magnificent royal fern (Osmunda regalis), though on a much humbler scale, bear their seed cases on independent stems, and were much sought after of old for imaginary virtues, which the modern schools of medicine refuse to recognize. Higher up the moor, ferns of ampler size occur, and what seems to be rushes, which bear atop conglobate panicles on their smooth leafless stems; but at its lower edge little else appears than the higher Acrogens,—ferns and their allies. There occurs, however, just beyond the first group of club mosses,—a remarkable exception in a solitary pine,—the advance guard of one of the ancient forests of the country, which may be seen far in the background, clothing with its shaggy covering of deep green the lower hill-slopes. And as we found in the Thallogens of that littoral zone over which we have just passed, representatives of the marine flora of the Silurian System, from the first appearance of organisms in its nether beds, to its bone-bed of the Upper Ludlow rocks, in which the Lycopodites first appear, so in the Acrogens of that moor, with its solitary coniferous tree, we may recognize an equally striking representative of the terrestrial flora which existed during the deposition of these Ludlow rocks, and of the various formations of the Old Red Sandstone, Lower, Middle, and Upper.
In the upper beds of the Upper Silurian, as has been already remarked, Lycopodites are the only terrestrial plants yet found. In the Lower Old Red Sandstone we find added to these, with Thallogens that bear at least the same general character as in the system beneath, minute ferns, and a greatly larger plant, allied to the horse tails. The Old Red flora seems to have been prevailingly an acrogenic flora; and yet with almost its first beginnings,—contemporary with at least the earlier fossils of the system in Scotland, we find a true polycotyledonous tree, not lower in the scale than the araucarites of the Coal Measures,—which in structure it greatly resembles,—or than the pines or cedars of our own times (see Fig. 3). In the Middle Old Red Sandstone there occurs, with plants representative apparently of the ferns and their allies, a somewhat equivocal and doubtful organism, which may have been the panicle or compound fruit of some aquatic rush; while in the Upper Old Red, just ere the gorgeous flora of the Coal Measures began to be, there existed in considerable abundance a stately fern, the Cyclopteris Hibernicus (see Fig. 2), of mayhap not smaller proportions than our monarch of the British ferns, Osmunda regalis, associated with a peculiar lepidodendron, and what seems to be a lepidostrobus,—possibly the fructiferous spike or cone of the latter, mingled with carbonaceous stems, which, in the simplicity of their texture, and their abundance, give evidence of a low but not scanty vegetation. Ere passing to the luxuriant carboniferous flora, I shall make but one other remark. The existing plants whence we derive our analogies in dealing with the vegetation of this early period, contribute but little, if at all, to the support of animal life. The ferns and their allies remain untouched by the grazing animals. Our native club mosses, though once used in medicine, are positively deleterious; the horse tails, though harmless, so abound in silex, which wraps them round with a cuticle of stone, that they are rarely cropped by cattle; while the thickets of fern which cover our hill-sides, and seem so temptingly rich and green in their season, scarce support the existence of a single creature, and remain untouched in stem and leaf, from their first appearance in spring, until they droop and wither under the frosts of early winter. Even the insects that infest the herbaria of the botanist almost never injure his ferns. Nor are our resin-producing conifers, though they nourish a few beetles, favorites with the herbivorous tribes in a much greater degree. Judging from all we yet know, the earliest terrestrial flora may have covered the dry land with its mantle of cheerful green, and served its general purposes, chemical and others, in the well-balanced economy of nature; but the herb-eating animals would have fared but ill even where it throve most luxuriantly; and it seems to harmonize with the fact of its non-edible character, that up to the present time we know not that a single herbivorous animal lived among its shades. From all that appears, it may be inferred that it had not to serve the purposes of the floras of the passing time, in which, according to the poet,
“The world’s bread depends on the shooting of a seed.”
The flora of the Coal Measures was the richest and most luxuriant, in at least individual productions, with which the fossil botanist has formed any acquaintance. Never before or since did our planet bear so rank a vegetation as that of which the numerous coal seams and inflammable shales of the carboniferous period form but a portion of the remains,—the portion spared, in the first instance, by dissipation and decay, and in the second by the denuding agencies. Almost all our coal,—the stored up fuel of a world,—forms but a comparatively small part of the produce of this wonderful flora. Amid much that was so strange and antique of type in its productions as to set the analogies of the botanist at fault, there occurred one solitary order, not a few of whose species closely resembled their cogeners of the present time. I refer, of course, to its ferns. And these seem to have formed no small proportion of the entire flora of the period. Francis estimates the recent dorsiferous ferns of Great Britain at thirty-five species, and the species of all the other genera at six more,—forty-one species in all; and as the flowering plants of the country do not fall short of fourteen hundred species, the ferns bear to them the rather small proportion of about one to thirty-five; whereas of the British Coal Measure flora, in which we do not yet reckon quite three hundred species of plants, about a hundred and twenty were ferns. Three sevenths of the entire carboniferous flora of Britain belonged to this familiar class; and for about fifty species more we can discover no nearer analogies than those which connect them with the fern allies. And if with the British Coal Measure we include those also of the Continent of America, we shall find the proportions in favor of the ferns still greater. The number of carboniferous plants hitherto described amounts, says M. Ad. Brogniart, to about five hundred, and of these two hundred and fifty,—one half of the whole,—were ferns.
| FERNS OF THE COAL MEASURES.6 |
Rising in the scale from the lower to the higher vegetable forms of the system,—from its ferns to its trees,—we find great conifers,—so great that they must have raised their heads more than a hundred feet over the soil; and such was their abundance in this neighborhood, that one can scarce examine a fragment of coal beside one’s household fire that is not charged with their carbonized remains. Though marked by certain peculiarities of structure, they bore, as is shown by the fossil trunks of Granton and Craigleith, the familiar outlines of true coniferous trees; and would mayhap have differed no more in appearance from their successors of the same order that now live in our forests, than these differ from the conifers of New Zealand or of New South Wales. We have thus, in the numerous ferns and numerous coniferous trees of the Coal Measures, known objects by which to conceive of some of the more prominent features of the flora of which they composed so large a part. We have not inadequate conceptions of at once the giants of its forests and the green swathe of its plains and hill-sides,—of its mighty trees and its dwarf underwood,—of its cedars of Lebanon, so to speak, and its hyssop of the wall. But of an intermediate class we have no existing representatives; and in this class the fossil botanist finds puzzles and enigmas with which hitherto at least he has been able to deal with only indifferent success. There is a view, however, sufficiently simple, which may be found somewhat to lessen, if not altogether remove, the difficulty. Nature does not dwell willingly in mediocrity; and so in all ages she as certainly produced trees, or plants of tree-like proportions and bulk, as she did minute shrubs and herbs. In not a few of the existing orders and families, such as the Rosaceæ, the Leguminosæ, the Myrtaceæ, and many others, we have plants of all sizes, from the creeping herb, half hidden in the sward, to the stately tree. The wild dwarf strawberry and minute stone-bramble are of the same order as our finer orchard trees,—apple, pear, and plum,—or as those noble hawthorn, mountain ash, and wild cherry trees, that impart such beauty to our lawns and woods; and the minute spring vetch and everlasting pea are denizens of the same great family as the tall locust and rosewood trees, and the gorgeous laburnum. Did there exist no other plants than the Rosaceæ or the Leguminosæ, we would possess, notwithstanding, herbs, shrubs, and trees, just as we do now. And in plants of a greatly humbler order we have instances of similar variety in point of size. The humblest grass in our meadows belongs to the same natural order as the tall bamboo, that, shooting up its panicles amid the jungles of India to the height of sixty feet, looks down upon all the second class trees of the country. Again, the minute forked spleenwort of Arthur Seat, which rarely exceeds three inches in length, is of the same family as those tree-ferns of New Zealand and Tasmania that rise to an elevation of from twenty to thirty feet. And we know how in the ferns provision is made for the attainment and maintenance of the tree-like size and character. The rachis, which in the smaller species is either subterranean or runs along the ground, takes in the tree-fern a different direction, and, rising erect, climbs slowly upwards in the character of a trunk or stem, and sends out atop, year after year, a higher and yet higher coronal of fronds. And in order to impart the necessary strength to this trunk, and to enable it to war for ages with the elements, its mass of soft cellular tissue is strengthened all round by internal buttresses of dense vascular fibre, tough and elastic as the strongest woods. Now, not a few of the more anomalous forms of the Coal Measures seem to be simply fern allies of the types Lycopodiaceæ, Marsileaceæ, and Equisetum, that, escaping from the mediocrity of mere herbs, shot up into trees,—some of them very great trees,—and that had of necessity to be furnished with a tissue widely different from that of their minuter contemporaries and successors. It was of course an absolute mechanical necessity, that if they were to present, by being tall and large, a wide front to the tempest, they should also be comparatively solid and strong to resist it; but with this simple mechanical requirement there seems to have mingled a principle of a more occult character. The Gymnogens or conifers were the highest vegetable existences of the period,—its true trees; and all the tree-like fern allies were strengthened to meet the necessities of their increased size, on, if I may so speak, a coniferous principle. Tissue resembling that of their contemporary conifers imparted the necessary rigidity to their framework; nay, so strangely were they pervaded throughout by the coniferous characteristics, that it seems difficult to determine whether they really most resembled the acrogenous or gymnogenous families. The Lepidodendra,—great plants of the club moss type, that rose from fifty to seventy feet in height,—had well nigh as many points of resemblance to the coniferæ as to the Lycopodites. The Calamites,—reed-like, jointed plants, that more nearly resemble the Equisetaceæ than aught else which now exists, but which attained, in the larger specimens, to the height of ordinary trees, also manifest very decidedly, in their internal structure, some of the characteristics of the conifers. It has been remarked by Lindley and Hutton of even Sphenophyllum,—a genus of plants with verticillate leaves, of which at least six species occur in our Coal Measures, and which Brogniart refers to one of the humblest families of the fern allies,—that it seems at least as nearly related to the Coniferæ as to its lowlier representatives, the Marsileaceæ. And it is this union of traits, pertaining to what are now widely separated orders, that imparts to not a few of the vegetables of the Coal Measures their singularly anomalous character.
LEPIDODENDRON STERNBERGII.9
Let me attempt introducing you more intimately to one of those plants which present scarce any analogy with existing forms, and which must have imparted so strange a character and appearance to the flora of the Coal Measures. The Sigillaria formed a numerous genus of the Carboniferous period: no fewer than twenty-two different species have been enumerated in the British coal fields alone; and such was their individual abundance, that there are great seams of coal which seem to be almost entirely composed of their remains. At least the ancient soil on which these seams rest, and on which their materials appear to have been elaborated from the elements, is in many instances as thickly traversed by their underground stems as the soil occupied by our densest forests is traversed by the tangled roots of the trees by which it is covered; and we often find associated with them in these cases the remains of no other plant. The Sigillaria were remarkable for their beautifully sculptured stems, various in their pattern, according to their species. All were fluted vertically, somewhat like columns of the Grecian Doric; and each flute or channel had its line of sculpture running adown its centre. In one species (S. flexuosa) the sculpture consists of round knobs, surrounded by single rings, like the heads of the bolts of the ship carpenter; in another (S. reniformis) the knobs are double, and of an oval form, somewhat resembling pairs of kidneys,—a resemblance to which the species owes its name. In another species (S. catenulata) what seems a minute chain of distinctly formed elliptical links drops down the middle of each flute; in yet another (S. oculata) the carvings are of an oval form, and, bearing each a round impression in its centre, they somewhat resemble rows of staring goggle-eyes; while the carvings in yet another species (S. pachyderma) consist chiefly of crescent-shaped depressions. The roots, or rather underground stems, of this curious genus attracted notice, from their singularity, long ere their connection with the carved and fluted stems had been determined, and have been often described as the “stigmaria” of the fossil botanist. They, too, have their curious carvings, consisting of deeply marked stigmata, quincuncially arranged, with each a little ring at its bottom, and, in at least one rare species, surrounded by a sculptured star. Unlike true roots, they terminate abruptly; each rootlet which they send forth was jointed to the little ring or dimpled knob at the bottom of the stigmata; and the appearance of the whole, as it radiated from the central mass, whence the carved trunk proceeded, somewhat resembled that of an enormous coach-wheel divested of the rim. Unfortunately we cannot yet complete our description of this strange plant. A specimen, traced for about forty feet across a shale bed, was found to bifurcate atop into two great branches,—a characteristic in which, with several others, it differed from most of the tree-ferns,—a class of plants to which Adolphe Brogniart is inclined to deem it related; but no specimen has yet shown the nature of its foliage. I am, however, not a little disposed to believe with Brogniart that it may have borne as leaves some of the supposed ferns of the Coal Measures; nowhere, at least, have I found these lie so thickly, layer above layer, as around the stems of Sigillaria; and the fact that, even in our own times, plants widely differing from the tree-ferns,—such, for instance, as one of the Cycadeæ,—should bear leaves scarce distinguishable from fern fronds, may well reconcile us to an apparent anomaly in the case of an ancient plant such as Sigillaria, whose entire constitution, so far as it has been ascertained, appears to have been anomalous. The sculpturesque character of this richly fretted genus was shared by not a few of its contemporaries. The Ulodendra, with their rectilinear rows of circular scars, and their stems covered with leaf-like carvings, rivalled in effect the ornately relieved torus of a Corinthian column: Favularia, Knorria, Halonia, many of the Calamites, and all the Lepidodendra, exhibited the most delicate sculpturing. In walking among the ruins of this ancient flora, the Palæontologist almost feels as if he had got among the broken fragments of Italian palaces, erected long ages ago, when the architecture of Rome was most ornate, and every moulding was roughened with ornament; and in attempting to call up in fancy the old Carboniferous forests, he has to dwell on this peculiar feature as one of the most prominent, and to see, in the multitude of trunks darkened above by clouds of foliage, that rise upon him in the prospect, the slim columns of an elder Alhambra, roughened with arabesque tracery and exquisite filagree work.
(Recent.)
In the Oolitic flora we find a few peculiar features introduced. The Cyeadeæ,—a family of plants allied to the ferns on the one hand, and to the conifers on the other, and which in their general aspect not a little resemble stunted palms,—appear in this flora for the first time. Its coniferous genera, too, receive great accessions to their numbers, and begin to resemble, more closely than at an earlier period, the genera which still continue to exist. The cypresses, the yews, the thujas, the dammaras, all make their earliest appearance in the flora of the Oolite. Among our existing woods there seem to be but two conifers (that attain to the dignity of trees) indigenous to Britain,—the common yew, Taxus baccata, and the common Scotch fir, Pinus sylvestris; and yet we know that the latter alone formed, during the last few centuries, great woods, that darkened for many miles together the now barren moors and bare hill-sides of the Highlands of Scotland,—moors and hill-sides that, though long since divested of their last tree, are still known by their old name of forests. In the times of the Oolite, on the other hand, Britain had from fourteen to twenty different species of conifers; and its great forests, of whose existence we have direct evidence in the very abundant lignites of the system, must have possessed a richness and variety which our ancient fir woods of the historic or human period could not have possessed. With the Conifers and the Cycadeæ there were many ferns associated,—so many, that they still composed nearly two fifths of the entire flora; and associated with these, though in reduced proportions, we find the fern allies. The reduction, however, of these last is rather in species than in individuals. The Brora Coal, one of the most considerable Oolitic seams in Europe, seems to have been formed almost exclusively of an equisetum,—E. columnare. In this flora the more equivocal productions of the Coal Measures are represented by what seems to be the last of the Calamites; but it contains no Lepidodendra,—no Ulodendra,—no Sigillaria,—no Favularia,—no Knorria or Halonia. Those monsters of the vegetable world that united to the forms of its humbler productions the bulk of trees, had, with the solitary exception of the Calamites, passed into extinction; and ere the close of the system they too had disappeared. The forms borne by most of the Oolitic plants were comparatively familiar forms. With the Acrogens and Gymnogens we find the first indication of the Liliaceæ, or lily-like plants,—of plants, too, allied to the Pandanaceæ or screw pines, the fruits of which are sometimes preserved in a wonderfully perfect state of keeping in the Inferior Oolite, together with Carpolithes,—palm-like fruits, very ornately sculptured,—and the remains of at least one other monocotyledon, that bears the somewhat general name of an Endogenite. With these there occur a few disputed leaves, which I must persist in regarding as dicotyledonous. But they formed, whatever their true character, a very inconspicuous feature in the Oolitic flora; and not until the overlying Cretaceous System is ushered in do we find leaves in any considerable quantity decidedly of this high family; nor until we enter into the earlier Tertiaries do we succeed in detecting a true dicotyledonous tree. On such an amount of observation is this order of succession determined,—though the evidence is, of course, mainly negative,—that when, some eight or ten years ago, Dr. John Wilson, the learned Free Church missionary to the Parsees of India, submitted to me specimens of fossil woods which he had picked up in the Egyptian Desert, in order that I might if possible determine their age, I told him, ere yet the optical lapidary had prepared them for examination, that if they exhibited the coniferous structure, they might belong to any geologic period from the times of the Lower Old Red Sandstone downwards; but that if they manifested in their tissue the dicotyledonous character, they could not be older than the times of the Tertiary. On submitting them in thin slices to the microscope, they were found to exhibit the peculiar dicotyledonous structure as strongly as the oak or chestnut. And Lieutenant Newbold’s researches in the deposit in which they occur has since demonstrated, on stratigraphical evidence, that not only does it belong to the great Tertiary division, but also to one of the comparatively modern formations of the Tertiary.
(Reduced one third.)
The earlier flora of this Tertiary division presents an aspect widely different from that of any of the previous ones. The ferns and their allies sink into their existing proportions; nor do the coniferæ, previously so abundant, occupy any longer a prominent place. On the other hand, the dicotyledonous herbs and trees, previously so inconspicuous in creation, are largely developed. Trees of those Amentiferous orders to which the oak, the hazel, the beech, and the plane belong, were perhaps not less abundant in the Eocene woods than in those of the present time: they were mingled with trees of the Laurel, the Leguminous, and the Anonaceous or custard apple families, with many others; and deep forests, in the latitude of London (in which the intertropical forms must now be protected, as in the Crystal Palace, with coverings of glass, and warmed by artificial heat), abounded in graceful palms. Mr. Bowerbank found in the London clay of the island of Sheppey alone the fruits of no fewer than thirteen different species of this picturesque family, which lends so peculiar a feature to the landscapes in which it occurs; and ascertained that the undergrowth beneath was composed, in large proportion, of creeping plants of the gourd and melon order. From the middle or Miocene flora of the Tertiary division,—of which we seem to possess in Britain only the small but interesting fragment detected by his Grace the Duke of Argyll among the trap-beds of Mull,—most of the more exotic forms seem to have been excluded. The palms, however, still survive in no fewer than thirty-one different species, and we find in great abundance, in the place of the other exotics, remains of the plane and buckthorn families,—part of a group of plants that in their general aspect, as shown in the Tertiary deposits of the Continent, not a little resembled the vegetation of the United States at the present day. The nearer we approach to existing times, the more familiar in form and outline do the herbs and trees become. We detect, as has been shown, at least one existing order in the ferns of the Coal Measures; we detect at least existing genera among the Coniferæ, Equisetaceæ, and Cycadaceæ of the Oolite; the acacias, gourds, and laurels of the Eocene flora, and the planes, willows, and buckthorns of the Miocene, though we fail to identify their species with aught that now lives, still more strongly remind us of the recent productions of our forests or conservatories; and, on entering, in our downward course, the Pleistocene period, we at length find ourselves among familiar species. On old terrestrial surfaces, that date before the times of the glacial period, and underlie the boulder clay, the remains of forests of oak, birch, hazel, and fir have been detected,—all of the familiar species indigenous to the country, and which still flourish in our native woods. And it was held by the late Professor Edward Forbes, that the most ancient of his five existing British floras,—that which occurs in the south-west of Ireland, and corresponds with the flora of the northwest of Spain and the Pyrenees,—had been introduced into the country as early, perhaps, as the times of the Miocene. Be this, however, as it may, there can rest no doubt on the great antiquity of the prevailing trees of our indigenous forests.
The oak, the birch, the hazel, the Scotch fir, all lived, I repeat, in what is now Britain, ere the last great depression of the land. The gigantic northern elephant and rhinoceros, extinct for untold ages, forced their way through their tangled branches; and the British tiger and hyæna harbored in their thickets. Cuvier framed an argument for the fixity of species on the fact that the birds and beasts embalmed in the catacombs were identical in every respect with the animals of the same kinds that live now. But what, it has been asked, was a brief period of three thousand years, compared with the geologic ages? or how could any such argument be founded on a basis so little extended? It is, however, to no such narrow basis we can refer in the case of these woods. All human history is comprised in the nearer corner of the immense period which they measure out; and yet, from their first appearance in creation till now they have not altered a single fibre. And such, on this point, is the invariable testimony of Palæontologic science,—testimony so invariable, that no great Palæontologist was ever yet an asserter of the development hypothesis. With the existing trees of our indigenous woods it is probable that in even these early times a considerable portion of the herbs of our recent flora would have been associated, though their remains, less fitted for preservation, have failed to leave distinct trace behind them. We at least know generally, that with each succeeding period there appeared a more extensively useful and various vegetation than that which had gone before. I have already referred to the sombre, unproductive character of the earliest terrestrial flora with which we are acquainted. It was a flora unfitted, apparently, for the support of either graminivorous bird or herbivorous quadruped. The singularly profuse vegetation of the Coal Measures was, with all its wild luxuriance, of a resembling cast. So far as appears, neither flock nor herd could have lived on its greenest and richest plains; nor does even the flora of the Oolite seem to have been in the least suited for the purposes of the shepherd or herdsman. Not until we enter on the Tertiary periods do we find floras amid which man might have profitably labored as a dresser of gardens, a tiller of fields, or a keeper of flocks and herds. Nay, there are whole orders and families of plants of the very first importance to man which do not appear until late in even the Tertiary ages. Some degree of doubt must always attach to merely negative evidence; but Agassiz, a geologist whose statements must be received with respect by every student of the science, finds reason to conclude that the order of the Rosaceæ,—an order more important to the gardener than almost any other, and to which the apple, the pear, the quince, the cherry, the plum, the peach, the apricot, the victorine, the almond, the raspberry, the strawberry, and the various brambleberries belong, together with all the roses and the potentillas,—was introduced only a short time previous to the appearance of man. And the true grasses,—a still more important order, which, as the corn-bearing plants of the agriculturist, feed at the present time at least two thirds of the human species, and in their humbler varieties form the staple food of the grazing animals,—scarce appear in the fossil state at all. They are peculiarly plants of the human period.
Let me instance one other family of which the fossil botanist has not yet succeeded in finding any trace in even the Tertiary deposits, and which appears to have been specially created for the gratification of human sense. Unlike the Rosaceæ, it exhibits no rich blow of color, or tempting show of luscious fruit;—- it does not appeal very directly to either the sense of taste or of sight: but it is richly odoriferous; and, though deemed somewhat out of place in the garden for the last century and more, it enters largely into the composition of some of our most fashionable perfumes. I refer to the Labiate family,—a family to which the lavenders, the mints, the thymes, and the hyssops belong, with basil, rosemary, and marjoram,—all plants of “gray renown,” as Shenstone happily remarks in his description of the herbal of his “Schoolmistress.”
“Herbs too she knew, and well of each could speak,
That in her garden sipped the silvery dew,
Where no vain flower disclosed a gaudy streak,
But herbs for use and physic not a few,
Of gray renown within those borders grew.
The tufted basil, pun-provoking thyme,
And fragrant balm, and sage of sober hue.
“And marjoram sweet in shepherd’s posie found,
And lavender, whose spikes of azure bloom
Shall be erewhile in arid bundles bound,
To lurk amid her labors of the loom,
And crown her kerchiefs clean with meikle rare perfume.
“And here trim rosemary, that whilom crowned
The daintiest garden of the proudest peer,
Ere, driven from its envied site, it found
A sacred shelter for its branches here,
Where, edged with gold, its glittering skirts appear,
With horehound gray, and mint of softer green.”
All the plants here enumerated belong to the labiate family; which, though unfashionable even in Shenstone’s days, have still their products favorably received in the very best society. The rosemary, whose banishment from the gardens of the great he specially records, enters largely in the composition of eau de Cologne. Of the lavenders, one species (Lavendula vera) yields the well known lavender oil, and another (L. latifolio) the spike oil. The peppermint (Meantha viridus) furnishes the essence so popular under that name among our confectioners; and one of the most valued perfumes of the East (next to the famous Attar, a product of the Rosaceæ) is the oil of the Patchouly plant, another of the labiates. Let me indulge, ere quitting this part of the subject, in a single remark. There have been classes of religionists, not wholly absent from our own country, and well known on the Continent, who have deemed it a merit to deny themselves every pleasure of sense, however innocent and delicate. The excellent but mistaken Pascal refused to look upon a lovely landscape; and the Port Royalist nuns remarked, somewhat simply for their side of the argument, that they seemed as if warring with Providence, seeing that the favors which he was abundantly showering upon them, they, in obedience to the stern law of their lives, were continually rejecting. But it is better, surely, to be on the side of Providence against Pascal and the nuns, than on the side of Pascal and the nuns against Providence. The great Creator, who has provided so wisely and abundantly for all his creatures, knows what is best for us, infinitely better than we do ourselves; and there is neither sense nor merit, surely, in churlishly refusing to partake of that ample entertainment, sprinkled with delicate perfumes, garnished with roses, and crowned with the most delicious fruit, which we now know was not only specially prepared for us, but also got ready, as nearly as we can judge, for the appointed hour of our appearance at the feast. This we also know, that when the Divine Man came into the world,—unlike the Port Royalists, he did not refuse the temperate use of any of these luxuries, not even of that “ointment of spikenard, very precious” (a product of the labiate family), with which Mary anointed his feet.
Though it may at first seem a little out of place, let us anticipate here, for the sake of the illustration which it affords, one of the sections of the other great division of our subject,—that which treats of the fossil animals. Let us run briefly over the geologic history of insects, in order that we may mark the peculiar light which it casts on the character of the ancient floras. No insects have yet been detected in the Silurian or Old Red Sandstone Systems. They first appear amid the hard, dry, flowerless vegetation of the Coal Measures, and in genera suited to its character. Among these the scorpions take a prominent place,—carnivorous arachnidæ of ill repute, that live under stones and fallen trunks, and seize fast with their nippers upon the creatures on which they prey, crustaceans usually, such as the wood-louse, or insects, such as the earth-beetles and their grubs. With the scorpions there occur cockroaches of types not at all unlike the existing ones, and that, judging from their appearance, must have been foul feeders, to which scarce anything could have come amiss as food. Books, manuscripts, leather, ink, oil, meat, even the bodies of the dead, are devoured indiscriminately by the recent Blatta gigantea of the warmer parts of the globe,—one of the most disagreeable pests of the European settler, or of war vessels on foreign stations. I have among my books an age-embrowned copy of Ramsay’s “Tea Table Miscellany,” that had been carried into foreign parts by a musical relation, after it had seen hard service at home, and had become smoke dried and black; and yet even it, though but little tempting, as might be thought, was not safe from the cockroaches; for, finding it left open one day, they ate out in half an hour half its table of contents, consisting of several leaves. Assuredly, if the ancient Blattæ were as little nice in their eating as the devourers of the “Tea Table Miscellany,” they would not have lacked food amid even the unproductive flora and meagre fauna of the Coal Measures. With these ancient cockroaches a few locusts and beetles have been found associated, together with a small Tinea,—a creature allied to the common clothes-moth, and a Phasmia,—a creature related to the spectre insects. But the group is an inconsiderable one; for insects seem to have occupied no very conspicuous place in the carboniferous fauna. The beetles appear to have been of the wood and seed devouring kinds, and would probably have found their food among the conifers; the Phasmidæ and grasshoppers would have lived on the tender shoots of the less rigid plants their contemporaries; the Tinea, probably on ligneous or cottony fibre. Not a single insect has the system yet produced of the now numerous kinds that seek their food among flowers. In the Oolitic ages, however, insects become greatly more numerous,—so numerous that they seemed to have formed almost exclusively the food of the earliest mammals, and apparently also of some of the flying reptiles of the time. The magnificent dragon-flies, the carnivorous tyrants of their race, were abundant; and we now know, that while they were, as their name indicates, dragons to the weaker insects, they themselves were devoured by dragons as truly such as were ever yet feigned by romancer of the middle ages. Ants were also common, with crickets, grasshoppers, bugs both of the land and water, beetles, two-winged flies, and, in species distinct from the preceding carboniferous ones, the disgusting cockroaches. And for the first time amid the remains of a flora that seems to have had its few flowers,—though flowers could have formed no conspicuous feature in even an Oolitic landscape,—we detect in a few broken fragments of the wings of butterflies, decided trace of the flower-sucking insects. Not, however, until we enter into the great Tertiary division do these become numerous. The first bee makes its appearance in the amber of the Eocene, locked up hermetically in its gem-like tomb,—an embalmed corpse in a crystal coffin,—along with fragments of flower-bearing herbs and trees. The first of the Bombycidæ too,—insects that maybe seen suspended over flowers by the scarce visible vibrations of their wings, sucking the honied juices by means of their long, slender trunks,—also appear in the amber, associated with moths, butterflies, and a few caterpillars. Bees and butterflies are present in increased proportions in the latter Tertiary deposits: but not until that terminal creation to which we ourselves belong was ushered on the scene did they receive their fullest development. There is exquisite poetry in Wordsworth’s reference to “the soft murmur of the vagrant bee,”—
“A slender sound, yet hoary Time
Doth to the soul exalt it with the chime
Of all his years; a company
Of ages coming, ages gone,
Nations from before them sweeping.”
And yet, mayhap, the naked scientific facts of the history of this busy insect are scarcely less poetic than the pleasing imagination of the poet regarding it. They tell that man’s world, with all its griefs and troubles, is more emphatically a world of flowers than any of the creations that preceded it, and that as one great family—the grasses—were called into existence, in order, apparently, that he might enter in favoring circumstances upon his two earliest avocations, and be in good hope a keeper of herds and a tiller of the ground; and as another family of plants—the Rosaceæ—was created in order that the gardens which it would be also one of his vocations to keep and to dress should have their trees “good for food and pleasant to the taste;” so flowers in general were profusely produced just ere he appeared, to minister to that sense of beauty which distinguishes him from all the lower creatures, and to which he owes not a few of his most exquisite enjoyments. The poet accepted the bee as a sign of high significance: the geologist also accepts her as a sign. Her entombed remains testify to the gradual fitting up of our earth as a place of habitation for a creature destined to seek delight for the mind and the eye as certainly as for the grosser senses, and in especial marks the introduction of the stately forest trees, and the arrival of the delicious flowers. And,
“Thus in their stations lifting toward the sky
The foliaged head in cloud-like majesty,
The shadow-casting race of trees survive:
Thus in the train of spring arrive
Sweet flowers: what living eye hath viewed
Their myriads? endlessly renewed
Wherever strikes the sun’s glad ray,
Where’er the subtile waters stray,
Wherever sportive zephyrs bend
Their course, or genial showers descend.”