These minor ranges, excepting the Zenta, are separated from the Andean masses by comparatively low depressions and are usually described as distinct ranges; topographically, however, they seem to form a continuation of the ranges running southward from the Santa Victoria and forming the eastern rampart of the great central plateau of which the Puna de Atacama covers a large part.
South of the Bermejo the land is more elevated and drier, though large depressions covered with marshy lagoons are to be found, similar to those farther north.
The water-courses and depressions of the shingly steppes afford pasturage sufficient for the guanaco, and in places support a thorny vegetation of low growth and starved appearance.
Lake Torrens, the largest of these depressions, sometimes forms a sheet of water 100 m.
The cells belonging to any given thread may be recognized at an early stage of growth, because each cell is connected with its neighbors belonging to the same thread by two depressions or pits, one at each end.
According to Lecointe, the young wall consists partly of cellulose and partly of a substance which is not cellulose, the latter existing in the form of slight depressions, which mark the position of the future pores.
Wide areas, giving rise to oceanic depressions and leaving the continents protuberant; the other, folding along comparatively narrow belts, giving rise to mountain ranges.
Within this space three depressions, all running S.W.
The depressions which gap the borders of the central plateau thus acquire a greater importance than the small differences in its vertical elevation.
Not a tree is to be seen, the few woods and thickets being hidden in the depressions and deep valleys of the rivers.
Innumerable clusters of wild cherries (Prunus Chamaecerasus), wild apricots (Amygdalus nana), the Siberian pea-tree (Caragana frutescens), and other deep-rooted shrubs grow at the bottoms of the depressions and on the slopes of the ravines, imparting to the steppe that charm which manifests itself in the popular poetry.
Some rivers, notably the Kur (Kyros, Araxes) which flows into the Bakhtegan lake east of Shiraz, drain into inland depressions or lakes.
On the one hand he may make the line follow the natural inequalities of the ground as nearly as may be, avoiding the elevations and depressions by curves; or on the other he may aim at making it as nearly straight and level as possible by taking it through the elevations in cuttings or tunnels and across the depressions on embankments or bridges.
An embankment-bank, or fill, is the reverse of a cutting, being an artificial mound of earth on which the railway is taken across depressions in the surface of the ground.
The kavirs, or salt depressions, of the Persian desert are more frequently widespread deposits of mud and salt than water-covered areas.
Although for the purposes of geographical nomenclature, boundaries formed by a coast-line - that is, by depressions of the earth's solid crust below the ocean level - are most easily recog- Political nized and are of special convenience; and although such divisions.
There are, it is true, mountain ranges which are formed of folded beds; but in many cases the direction of the chains is different from that of the folds, so that the ranges must owe their elevation to other causes; and the folds, moreover, are of ancient date, for the most part Archaean or Palaeozoic. The configuration of the region is largely due to faulting, trough-like or tray-like depressions being formed, and the intervening strips, which have not been depressed, standing up as mountain ridges.
Structurally, the folds of this region are of ancient date; but the area is crossed by a series of depressions formed by faults, and the intervening strips, which have not been depressed to the same extent, now stand up as mountain ranges.
They are found one on each cephalic tentacle, and are simply minute open pits or depressions of the epidermis, the epidermic cells lining them being pigmented and connected with nerves (compare fig.
The recognition of these, minute and fragmentary as many were, and the referring them to their proper place, rendered necessary an attentive study of the comparative osteology and myology of birds in general, that of the " long bones," whose sole characters were often a few muscular ridges or depressions, being especially obligatory.
The most striking feature in the structure of Syria is the existence of long Graben, or narrow depressions formed by faulting.
The faulting which formed the depressions is certainly later than the deposition of the Cretaceous beds and probably belongs to the later portion of the Tertiary era.
They are due largely to sinkholes or depressions caused by solution of the limestone of the region.
The depressions between the ridges are not filled up with cement.
Molecular Depressions of the Freezing Point.
There are, however, among these border-ranges several breaches of continuity - broad depressions or trenches leading from Lake Balkash and Lake Zaisan to the upper parts of the plateau.
All the valleys and depressions bear traces of immense post-Pliocene lakes.
The shores of all the lakes which filled the depressions during the Lacustrine period abound in remains dating from the Neolithic Stone period; and numberless kurgans (tumuli), furnaces and so on bear witness to a much denser population than the present.
In Magellania [Waldheimia] it is elongated and reflected; the hinge-plate large, with four depressions, under which originates a median septum, which extends more or less into the interior of the shell (figs.
H, Epidermic cell-layer; mes, mesoblastic connective tissue; n, nerves; II, III, IV, V, depressions of the epidermis in each of which a cuticular lens will be formed.
In the larger depressions, like that of the Reconcavo of Bahia, there are large alluvial areas celebrated for their fertility.
In the northern region are large marshy depressions, in which the water is often salt.
Conifera; the star represents the ciliated cup connected by ciliated depressions with the groove; 5, disk of Conochilus, like the Bdelloid, but with mouth antero-dorsal, the gap postero-ventral; 6, disk of Stephanoceroscingulum broken up into setiferous lobes, groove a naked funnel, trochus a horseshoe-shaped ridge, mouth central.
They may be divided into two classes; those of the plateau region which occupy lacustrine depressions and receive the drainage of the surrounding country; and the tide-water lagoons of the coast formed by the building up of new sand beaches across the indentations in the coast-line.
The two noteworthy depressions in its surface, the Valley of Mexico and Bolson de Mapimi, once contained large bodies of water, of which only small lakes and marshy lagoons now remain.
Deperet points also that we owe to Cuvier the first clear expression of the idea of the increasing organic perfection of all forms of life from the lower to the higher horizons, and that, while he believed that extinctions were due to sudden revolutions on the surface of the earth, he also set forth the pregnant ideas that the renewals of animal life were by migration from other regions unknown, and that these migrations were favoured by alternate elevations and depressions which formed various land routes between great continents and islands.
The Hohe Tauern contains many high lying valleys, traversed by the streams which flow into the Salzach, as well as numerous depressions and passes, here called popularly Tauern.
In the north-west, and is generally much less rugged than the Alleghany Plateau; a peculiar feature of the southern portion of it is the numerous circular depressions (sink holes) in the surface and the cavernous region beneath.
The average depth varies from 1500 to 2500 fathoms, and from this level innumerable volcanic ridges and peaks rise almost or quite to the surface, their summits for the most part occupied by atolls and reefs of coral formation, while interspersed with these are depressions, mostly of small area, among which the deepest soundings recorded have been obtained.
To the Pliocene period the marine deposits of the Sahel of Algiers and of the Sahel Jijelli must be attributed; also the lacustrine marls and limestone of the basin of Constantine, and the ancient alluviums of the basins and depressions which bear no relation to the existing valleys.
Behind the Tell is a lofty table-land with an average elevation of 3000 ft., consisting of vast plains, for the most part arid or covered with esparto grass, in the depressions of which are great salt lakes and swamps (Arabic, shats) fed by streams which can find no outlet to the sea through the encircling hills.
In numerous depressions, some of which may have been the beds of lakes formed by beaver dams, the soil is deep and largely of vegetable formation.