Mythical Monsters. Gould Charles

among others, which shows a fine regular finish, can, in my opinion, only have been shaped by man. Nevertheless, I do not blame those of my colleagues who deny or still doubt. In such a matter there is no very great urgency, and, doubtless, the existence of Miocene man will be proved, as that of Glacial and Pliocene has been, by facts.” Mr. Geikie, from whose work —Prehistoric Europe– I have summarized the above statements, says, in reference to this question: “There is unquestionably much force in what M. Quatrefages says; nevertheless, most geologists will agree with him that the question of man’s Miocene age still remains to be demonstrated by unequivocal evidence. At present, all that we can safely say is, that man was probably living in Europe near the close of the Pliocene period, and that he was certainly an occupant of our continent during glacial and interglacial times.”

      Professor Marsh considers that the evidence, as it stands to-day, although not conclusive, “seems to place the first appearance of man [in America] in the Pliocene, and that the best proofs of this are to be found on the Pacific coast.” He adds: “During several visits to that region many facts were brought to my knowledge which render this more than probable. Man, at this time, was a savage, and was doubtless forced by the great volcanic outbreaks to continue his migration. This was at first to the south, since mountain chains were barriers on the east,” and “he doubtless first came across Behring’s Straits.”

      I have hitherto assumed a certain acquaintance, upon the part of the general reader, with the terms Eocene, Miocene, and Pliocene, happily invented by Sir Charles Lyell to designate three of the four great divisions of the Tertiary age. These, from their universal acceptation and constant use, have “become familiar in our mouths as household words.” But it will be well, before further elaborating points in the history of these groups, bearing upon our argument, to take into consideration their subdivisions, and the equivalent or contemporary deposits composing them in various countries. This can be most conveniently done by displaying these, in descending order, in a tabular form, which I accordingly annex below. This is the more desirable as there are few departments in geological science which have received more attention than this; or in which greater returns, in the shape of important and interesting discoveries relative to man’s existence, have been made.

      Comparatively recent – comparatively, that is to say, with regard to the vast æons that preceded them, but extending back over enormous spaces of time when contrasted with the limited duration of written history, – they embrace the period during which the mainly existing distribution of land and ocean has obtained, and the present forms of life have appeared by evolution from preceding species, or, as some few still maintain, by separate and special creation.

      THE TERTIARY OR CAINOZOIC AGE.

      PLIOCENE.

      MIOCENE.

EOCENE

      The subdivisions of the Eocene have been worked out in great detail in Britain, France, and America. Those of most other countries have either not yet been fully studied or their exact equivalence remains undetermined.

      We learn, both from the nature of these deposits and from their organic contents, that climatic oscillations have been passing during the whole period of their deposition over the surface of the globe, and inducing corresponding fluctuations in the character of the vegetable and animal life abounding on it. A complete collation of these varying conditions at synchronous periods remains to be achieved, but the study of our own country, and those adjacent to it, shows that alternations of tropical, boreal, and temperate climate have occurred in it; a remarkable series of conditions which has only lately been thoroughly and satisfactorily accounted for.

      Thus, during a portion of the Eocene period a tropical climate prevailed, as is evidenced by deposits containing remains of palms of an equatorial type, crocodiles, turtles, tropical shells, and other remains attesting the existence of a high temperature. The converse is proved of the Pleistocene by the existence of a boreal fauna, and the widespread evidences of glacial action. The gradations of climate during the Miocene and Pliocene, and the amelioration subsequent to the glacial period, have resulted in the gradual development or appearance of specific life as it exists at present.

      Corresponding indications of secular variability of climate are derived from all quarters: during the Miocene age, Greenland (in N. Lat. 70°) developed an abundance of trees, such as the yew, the Redwood, a Sequoia allied to the Californian species, beeches, planes, willows, oaks, poplars, and walnuts, as well as a Magnolia and a Zamia. In Spitzbergen (N. Lat. 78° 56′) flourished yews, hazels, poplars, alders, beeches, and limes. At the present day, a dwarf willow and a few herbaceous plants form the only vegetation, and the ground is covered with almost perpetual ice and snow.

      Many similar fluctuations of climate have been traced right back through the geological record; but this fact, though interesting in relation to the general solution of the causes, has little bearing on the present purpose.

      Sir Charles Lyell conceived that all cosmical changes of climate in the past might be accounted for by the varying preponderance of land in the vicinity of the equator or near the poles, supplemented, of course, in a subordinate degree by alteration of level and the influence of ocean currents. When, for example, at any geological period the excess of land was equatorial, the ascent and passage northwards of currents of heated air would, according to his view, render the poles habitable; while, per contrâ, the excessive massing of land around the pole, and absence of it from the equator, would cause an arctic climate to spread far over the now temperate latitudes.

      The correctness of these inferences has been objected to by Mr. James Geikie and Dr. Croll, who doubt whether the northward currents of air would act as successful carriers of heat to the polar regions, or whether they would not rather dissipate it into space upon the road. On the other hand, Mr. Geikie, though admitting that the temperature of a large unbroken arctic continent would be low, suggests that, as the winds would be stripped of all moisture on its fringes, the interior would therefore be without accumulations of snow and ice; and in the more probable event of its being deeply indented by fjords and bays, warm sea-currents (the representatives of our present Gulf and Japan streams, but possessing a higher temperature than either, from the greater extent of equatorial sea-surface originating them, and exposed to the sun’s influence) would flow northward, and, ramifying, carry with them warm and heated atmospheres far into its interior, though even these, he thinks, would be insufficient in their effects under any circumstances to produce the sub-tropical climates which are known to have existed in high latitudes.

      Mr. John Evans75 has thrown out the idea that possibly a complete translation of geographical position with respect to polar axes may have been produced by a sliding of the whole surface crust of the globe about a fluid nucleus. This, he considers, would be induced by disturbances of equilibrium of the whole mass from geological causes. He further points out that the difference between the polar and equatorial diameters of the globe, which constitutes an important objection to his theory, is materially reduced when we take into consideration the enormous depth of the ocean over a large portion of the equator, and the great tracts of land elevated considerably above the sea-level in higher latitudes. He also speculates on the general average of the surface having in bygone geological epochs approached much more nearly to that of a sphere than it does at the present time.

      Sir John Lubbock favoured the idea of a change in the position of the axis of rotation, and this view has been supported by Sir H. James76 and many later geologists.77 If I apprehend their arguments correctly, this change could only have been produced by what may be termed geological revolutions. These are great outbursts of volcanic matter, elevations, subsidences, and the like. These having probably been almost continuous throughout geological time, incessant changes, small or great, would be demanded in the position of the axis,

75

Proceedings, Royal Society, vol. xv. No. 82, 1866.

76

Athenæum, August 25, 1860, &c.

77

The mass of astronomers, however, deny that this is possible to any very great extent.