Upon it, in the trough thus formed, rest conformably the basal strata of the Cretaceous; the Jurassic and Triassic being wholly absent (unless in the extreme north-west).
The Atlantic anticyclone is, therefore, at its weakest in winter, and on its polar side the polar eddy becomes a trough of low pressure, extending roughly from Labrador to Iceland and Jan Mayen, and traversed by a constant succession of cyclones.
This rise is separated from the Crozet Rise by a depression extending to 2675 fathoms, through which the Kerguelen Trough (which lies north of Kerguelen) is brought into free communication with the Indo-Atlantic Antarctic Basin.
Geographically the Safed Koh is not an isolated range, for there is no break in the continuity of water divide which connects it with the great Shandur offshoot of the Hindu Kush except the narrow trough of the Kabul river, which cuts a deep waterway across where it makes its way from Dakka into the Peshawar plains.
Thus although the rocks of the southern coast of Java in their general character and succession resemble those of Christmas Island, there lies between them an abysmal trough 18,000 ft.
The western trough extends northwards into Davis Strait, forming a depression in the Telegraph plateau; to the south of Newfoundland and Nova Scotia are Sigsbee Deep, Libbey Deep and Suhm Deep, each of small area; north-east of the Bahamas Nares Deep forms the largest and deepest depression in the Atlantic, in which a sounding of 4561 fathoms was obtained (70 m.
Above the sea, and occupies the southern end of the great central rift-valley, which terminates suddenly at its southern point, the line of depression being represented farther south by the more easterly trough of Lakes Nyasa and Rukwa, from which Tanganyika is separated by the Fipa plateau, composed of old granitoid rocks; though even here traces of old valley-walls are said by Dr Kohlschiitter to exist.
Turning on the water, she filled their water trough before heading out for the longhorn shed, which was the closest to the trees.
Northwards from the Hindu Kush (it is across this range that the route from Zebak to Ishkashim lies), which determines the great bend of the Oxus river northwards from Ishkashim, and narrows the valley of that river into the formation of a trough as far as the next bend westwards at Kala Wamar.
Talon shoved her back into the valley with a snarled threat under his breath, and she hurried out of the trough again, breathing hard by the time she'd clambered twenty feet to the top.