Plataea

“ The finest example is, perhaps, the dark-gray Plato, situated in 50° of north latitude, near an immense mountain uplift named the Lunar Alps, and on the northern shore of the Mare Imbrium, or "Sea of Showers." Plato appears as an oval plain, very smooth and level, about 60 miles in length, and completely surrounded by mountains, quite precipitous on the inner side, and rising in their highest peaks to an elevation of 6,000 to [Pg 226] 7,000 feet. ”

“ If, for example, we have a series of formations, A, B, C, piled one on the top of the other, A being the lowest, and C the highest, and each charged with its own peculiar fossils, we may compare the fossils met with in other sets of strata with the organic remains found in A, B, C. Should the former be found to correspond with the fossil contents of B, we conclude that the rocks in which they occur are approximately of contemporaneous origin with B, even although the equivalents of the formations A and C should be entirely wanting. ”

“ At one level, for example, univalve shells of some one or more species predominate; at another, bivalve shells; and at a third, corals; while in some formations we find layers of vegetable matter, commonly derived from land plants, separating strata.
It may appear inconceivable to a beginner how mountains, several thousand feet thick, can have become full of fossils from top to bottom; but the difficulty is removed, when he reflects on the origin of stratification, as explained in the last chapter, and allows sufficient time for the accumulation of sediment. ”

“ Of the interchangeable elements, fire, the rarest, can only become a denser, and water, the densest, only a rarer: but air may become a denser or a rarer. No single particle of the elements is visible, but only the aggregates of them are seen. The subordinate species depend, not upon differences of form in the original triangles, but upon differences of size. The obvious physical phenomena from which Plato has gathered his views of the relations of the elements seem to be the effect of fire upon air, water, and earth, and the effect of water upon earth. ”

“ The records of fossil species must occupy a prominent position in the data by which we may hope to solve some at least of the problems of plant evolution. From the point of view of distribution, palaeobotany is of considerable value, not only to the student of geographical botany, but to the geologist, who endeavours to map out the positions of ancient continents with the help of palaeontological evidence. The present distribution of plants and animals represents but one chapter in the history of life on the Earth ”

“ Six of these squares joined together formed eight solid angles, each produced by three plane right angles: and the shape of the body thus formed was cubical, having six square planes for its surfaces.” In his cosmology Plato assigned this solid to “earth,” for “‘earth’ is the least mobile of the four (elements—‘fire,’ ‘water,’ ‘air’ and ‘earth’) and most plastic of bodies: and that substance must possess this nature in the highest degree which has its bases most stable.” The mensuration of the cube, and its relations to other geometrical solids are treated in the article Polyhedron ”

“ The tertiary strata described in the preceding chapters are all of them characterized by fossil shells, of which a considerable proportion are specifically identical with the living mollusca; and the greater the number, the more nearly does the entire fauna approach in species and genera to that now inhabiting the adjoining seas. But in the Eocene formations next to be considered, the proportion of recent species is very small, and sometimes scarcely appreciable, and those agreeing with the fossil testacea often belong to remote parts of the globe, and to various zoological provinces. ”

“ It will be remembered that the fortieth degree of north latitude passed through Atlantis. Plato knew ("Dialogues, Phædo," 108) that the earth "is a body in the centre of the heavens" held in equipoise. He speaks of it as a "round body," a "globe;" he even understood that it revolved on its axis, and that these revolutions produced day and night. He says—"Dialogues, Timæus"—"The earth circling around the pole (which is extended through the universe) he made to be the artificer of night and day." All this Greek learning was probably drawn from the Egyptians. ”

“ Plates II to VII of the first part appear to relate to one general subject, if we can judge of this by the figures and symbols, but what that general subject is I am as yet unable to determine positively, but am of the opinion that they relate, in part at least, to the festivals and profession of the traveling merchants.
The first division of Plate II contains two figures. The one to the left, a quadruped upon a brown ground, has its hind feet upon an oblong figure, apparently a stone, holding by its fore feet to a cord which passes round the object on which its hind feet are placed. ”

“ When we examine a large area such as Europe, the average as well as the extreme height above the sea attained by the older formations is usually found to exceed that reached by the more modern ones, the primary or palaeozoic rising higher than the secondary, and these in their turn than the tertiary; while in reference to the three divisions of the tertiary, the lowest or Eocene group attains a higher summit-level than the Miocene, and these again a greater height than the Pliocene formations. ”

“ Various are the genera and species of once animate forms, imbedded in the different strata beneath our feet; but equally various are the strata themselves; as a new race arises, so are there new forms of rocks produced along with them. And when we compare the two extremes of the fossiliferous strata, the silurian and the tertiary, or any of the intermediate—the old red sandstone and the oolites, the carboniferous and the chalk—we find that the rocks are just as various in quality, structure, and appearance, as are the animals which existed and perished during their respective epochs. ”

“ The plain of Atlantis, Plato tells us, "had been cultivated during many ages by many generations of kings." If, as we believe, agriculture, the domestication of the horse, ox, sheep, goat, and hog, and the discovery or development of wheat, oats, rye, and barley originated in this region, then this language of Plato in reference to "the many ages, and the successive generations of kings," accords with the great periods of time which were necessary to bring man from a savage to a civilized condition. ”

“ Any area of approximately horizontal strata of aqueous origin, rising to a height of a thousand feet or more above the sea, would come under this class of plateau—the plateau of the Colorado being a good example. Although that plateau is of recent — 45 — origin, yet its surface, as we have seen, has been profoundly modified by superficial erosion; and this is true to a greater extent of plateaux which have been much longer exposed to denudation. It is obvious that even mountains and plateaux of accumulation often owe many of their present features to the action of the surface-agents of change. ”

“ We have represented, in Figs. 3-12, leaves of the following genera:Platanus, Populus, Juglans, Corylus, Carpinus, Persea, Mens, Sequoia, Comics [2] These names are all familiar, although we are not accustomed to see them grouped together. Platanus is represented throughout the northern Mississippi Valley by the sycamore, frequenting the water-courses and rocky banks, and often attaining grand dimensions. Two species of the genus occur in California, two in Mexico, and one in the far Levant. ”

“ A few species may pass from the one into the other, or perhaps every species may be different. In cases of this kind, when proved to be not merely local but persistent over wide areas, we must admit, notwithstanding the apparently undisturbed and continuous character of the original deposition of the strata, that the abrupt transition from the one facies of fossils to the other represents a long interval of time which has not been recorded by the deposit of strata. ”

“ Besides, were we to consider it in this view, the recent and fossil remains would be found to throw a mutual light upon each other, and the naturalist would not be so often at a loss to class every new fossil acquisition, of which the recent specimen is not to be found, especially whenever the fossil has any thing seemingly æquivocal in its formation, so as on a superficial imspection to render the matter doubtful, whether the body belongs to the animal or vegetable kingdoms, or indeed to either of them. ”

“ Every exploration of new areas, and every closer inspection of areas already explored, brings more types to light. And beyond question, an exhaustive examination of all exposed strata, and of all strata now covered by the sea, would disclose types immensely out-numbering those at present known. Further, geologists agree that even had we before us every kind of fossil which exists, we should still have nothing like a complete index to the past inhabitants of our globe. ”

“ The plant-remains of the Lower Cretaceous greatly resemble those of the Jurassic period, consisting mainly of Ferns, Cycads, and Conifers. The Upper Cretaceous rocks, however, both in Europe and in North America, have yielded an abundant flora which resembles the existing vegetation of the globe in consisting mainly of Angiospermous Exogens and of Monocotyledons. ”

“ Thus Plato, who represents most clearly this advance in the interpretation of facts, imagined that each particular kind of plant or animal had its shape inevitably determined by something which he termed an idea, a shape-giving power which existed before the object was created, and which would remain after it had been destroyed, ever ready again to bring matter to the particular form. ”

“ Of the kinds of earth, that which is filtered through water passes into stone; the water is broken up by the earth and escapes in the form of air—this in turn presses upon the mass of earth, and the earth, compressed into an indissoluble union with the remaining water, becomes rock. Rock, when it is made up of equal particles, is fair and transparent, but the reverse when of unequal. Earth is converted into pottery when the watery part is suddenly drawn away; or if moisture remains, the earth, when fused by fire, becomes, on cooling, a stone of a black colour. ”

“ The three broad divisions—Palaeozoic, Mesozoic, Cainozoic—which are employed by geologists to mark three stages in the development of life on the earth, are based primarily upon the fossil contents of the strata which, at one time or another, have been continuously forming since the earliest times. ”

“ Though at present geological investigations have not been prosecuted in all accessible parts of the land, so as every where to bring proof of the universality of these laws of successive systems of life, enough is known to assure us that in every country yet examined, the fossils of the tertiary, secondary, and primary strata differ essentially, and by large and general characters. ”

“ In the Miocene deposits, which are next in succession to the Eocene, we begin to find a considerable number, although still a minority, of recent species, intermixed with some fossils common to the preceding epoch. We then arrive at the Pliocene strata, in which species now contemporary with man begin to preponderate, and in the newest of which nine-tenths of the fossils agree with species still inhabiting the neighboring sea. ”

“ The following remarks of the Professor would apply almost as well to the Miocene implements as to those of the plateau—
"Unlike the valley implements, the plateau implements are, as a rule, made of the fragments of natural drift flints, that are found scattered over the surface of the ground, or picked up in gravel-beds and merely roughly trimmed. Sometimes the work is so slight as to be scarcely apparent; at others, it is sufficient to show a distinct design and object. ”

“ Many observers had noted that recent strata everywhere show a fossil fauna more nearly like the existing one than do more ancient strata; and that fossils from any two consecutive strata are far more closely related to each other than are the fossils of two remote formations, the fauna of each geological formation being, indeed, in a wide view, intermediate between preceding and succeeding faunas. ”

“ Facts of a very similar nature are offered by the succession of Plants upon the globe. Thus the vegetation of the Palæozoic period consisted principally of the lowly-organised groups of the Cryptogamous or Flowerless plants. The Mesozoic formations, up to the Chalk, are especially characterised by the naked-seeded Flowering plants—the Conifers and the Cycads; whilst the higher groups of the Angiospermous Exogens and Monocotyledons characterise the Upper Cretaceous and Tertiary rocks. ”

“ Tens of thousands of species have come and gone. Accepting this fact, it is then clear that strata which were formed at notably different times must contain notably different fossils, while strata which accumulated at practically the same time contain similar fossils, allowing, of course, for reasonable differences in geographical distribution of organisms as at the present time. Each epoch of earth history or series of strata has its characteristic assemblage of organisms. ”

“ The imperfection and want of continuity of the records in Europe have made it necessary in dealing with the Cretaceous European Cretaceous. floras for us to give the first place to America. But it is now advisable to return to Europe, where Upper Cretaceous plants are not uncommon, and the position of the deposits in the Cretaceous series can often be fixed accurately by their close association with marine strata belonging to definite subdivisions. ”