From the Caspian to Karachi it is possible to pass without encountering any orographic obstacle greater than the divide which separates the valley of the Hari Rud from the Helmund hamun basin, which may be represented by an altitude of about 4000 ft.
The supreme orographic importance of this great Central Asian mountain system was recognized in a fashion even by the geographers of ancient Greece.
The orographic features of the Pacific Mountain system trend parallel to the coast-line of the Gulf of Alaska, changing with this at the great bend beyond the N., and of the Panhandle from S.E.
The border-ridge character of the Sayans (Ergik-targak-taiga) is well established, and the same orographic character is confirmed by recent explorers with regard to the Sailughem range of the Altai.
While it is throughout essentially a mountainous country, very complicated in its orographic features and interlocking river systems, two principal mountain axes form its ruling features - the Rocky Mountains proper, above referred to, and the Coast Ranges.
West of the Cordillera Oriental, where special conditions prevail, a great desert plateau stretches entirely across one corner of the republic. Apart from the Andean system there is a group of low, broken, gneiss ranges stretching along the east side of Bolivia among the upper affluents of the Mamore and Guapore, which appear to belong to the older Brazilian orographic system, from which they have been separated by the erosive action of water.
From an orographic point of view, Bohemia constitutes amongst the Austrian provinces a separate massif, bordered on three sides by mountain ranges: on the S.W.
The rainfall of England, being largely due to passing cyclones, can hardly be expected to show a very close relation to the physical features of the country, yet looked at in a general way the relation between prevailing winds and orographic structure is not obscure.
The western or mountainous division is the wettest at all seasons, each orographic group forming a centre of heavy precipitation.
The Abyssinian highlands are thus a clearly marked orographic division.
The outstanding orographic feature of the country is the terrace-formation of the land, which rises from sea-level by well-marked steps to the immense plateau which forms seven-eighths of South Africa.
On its northern side the valley of Borotala is skirted by the important orographic system of the Dzungarian Ala-tau, the northernmost member of the Tian-shan.
In consequence of this peculiarity, climatic or orographic changes in Europe tend to drive animals and plants into a cul de sac, from which there is no escape; but in America similar climatic waves merely cause the species alternately to retreat and advance.
High, forming a confused orographic system, which is by no means fully understood.
In the case of general maps on a smaller scale, the orographic features must be generalized by a skilful draughtsman and artist.