This principle has been demonstrated recently among Tertiary rhinoceroses and titanotheres, in which remains of four or five genetic series in the same geologic deposits have been discovered.
Brown; folios 26, 28, 32, 34, 44, 69, 7 2, 77 and 160 of the Geologic Atlas of the United States; M.
Abich (Sur la structure et la geologic du Daghestan, 1862), the successive folds of Jurassic limestones and slates, all nearly parallel to the Caucasus, which form lofty, narrow plateaus.
This is not due to environmental conditions solely, because senescent branches of normal progressive groups are found in all geologic horizons, beginning, for gastropods, in the Lower Cambrian.
In the order of decreasing geologic age and maturity.
The mountain chains, which from their peculiar geologic character are known as of the "Basin Range type" (not exactly conterminous in distribution with the Basin), are echeloned in short ranges running from N.
Igneous intrusions consist only of unimportant dikes of trap. The most striking and uniformly characteristic geologic feature of the mountains is their internal structure, consisting of innumerable parallel, long and narrow folds, always closely appressed in the eastern part of any crosssection (Piedmont Plateau to Great Valley), less so along a central zone (Great Valley and Valley Ridges), and increasingly open on the west (Allegheny and Cumberland Plateaus).
These were successive stages in the geologic process which has created, and is still actively modifying, the state.
The geologic record is, as perhaps is to be expected, exceedingly poor, except as regards the calcareous Siphonales, which are well represented at various horizons, from the Silurian to the Tertiary; even the Diatomaceae, which are found in great quantities in the Tertiary deposits, do not occur at all earlier than the chalk.
For Geology see Tchihatcheff, Asie Mineure, Geologic (Paris, 1867-1869); Schaffer, Cilicia, Peterm.
There is ample proof throughout the country of alterations of level within recent geologic periods; and there have even been compressions, resulting in a relative rise of the ground, over the crests of anticlinal folds, within historic record.
Such a drying up has been in progress during long geologic ages, but doubt exists as to its practical importance at the present time.
Its upheaval above the great sea which submerged all the north-west of the Indian peninsula long after the Himalaya had massed itself as a formidable mountain chain, belongs to a comparatively recent geologic period, and the same thrust upwards of vast masses of cretaceous limestone has disturbed the overlying recent beds of shale and clays with very similar results to those which have left so marked an impress on the Baluch frontier.
For its significance as a former (geologic) connexion between the Sea of Azov and the Caspian Sea, see Caspian Sea.
See the separate articles on the states, and also the following references: - Topographic maps and Geologic Folios of the United States Geological Survey; Bailey Willis, "The Northern Appalachians," and C. W.
These horses are of the same geologic age (Upper Miocene) and 'were found in the same geographic region (South Dakota, U.S.A.).
Salisbur Geologic Processes (New York) and Earth History (2 vols., New York J.
The theory of past migrations from continent to continent, suggested by Cuvier to explain the replacement of the animal life which had become extinct through sudden geologic changes, was prophetic of one of the chief features of modern method - namely, the tracing of migrations.
19 a nuances, or grades of difference, which are the more gradual the more finely we dissect the geologic column, while the terms species, sub-species and variety are generally based upon a sum of changes in several characters.