Comparative geography

by Carl Ritter

To meet and counteract the errors alluded to above, and current in the loose language of popular speech, we shall use a new and indeed arbitrary terminology,—arbitrary because the data which mensuration will sometimes furnish are now, in part, wanting. We will divide the earth not relatively, but absolutely, into highlands and lowlands. The great districts often met, whose elevations are very moderate, we call lowlands. They are, for the most part, immense plains, varied but little above the level of the sea. The great districts which inclose mountain ranges we call highlands, and sometimes plateaus. True highlands can often embrace very extended and elevated plains, and these plains again may include hills and mountains. This does not affect their character as highlands, which lies in the fact of elevation rather than in more or less modified variation of surface. There may be vast variety in the physical manifestations of a great plateau district, entirely independent of the relative effects produced by the distribution of its surface into plains, rolling land, hills, and mountains.

In the lowlands there may exist hills to some extent, and these may even be combined in ranges, provided only that they do not violate the uniform characteristics of the district in which they are found.

The highlands are generally met with in the interior of the continents; the lowlands at the coasts. Yet there are exceptions to this.

In the transitions from lowlands to highlands there is great diversity. We can speak of three distinct bases of discrimination: a sudden and abrupt ascent; a rise in elevation so gradual as scarcely to be perceived; and a terrace formation. Yet in these there is a blending of one variety with another; there is no place sharply marked, where we can say that one form ends and another begins. There are constantly found modifications of these three transitional phases. The plains along the Indus and the Ganges rise sharply to the plateaus of Thibet The flat Pacific coast of South America is exchanged with equal abruptness for the highlands of Peru. The transition is a gradual one from the lowlands of North Germany, along the Baltic and the North Sea, through Saxony and Bohemia to the Bavarian highlands, north of the Alps. The Spanish highlands form a series of terraces, increasing in height from south to north. The immense plateaus of central Asia are also terrace formations, of diminishing elevation, as they advance to Siberia; so, too, are the eastern plateaus of Peru, falling off in altitude toward the plains of the Amazon.

Just as varied are the heights taken from the sea level of the leading plateaus. Yet they never rise to a point of elevation comparable with those of isolated mountain peaks or ranges. These attain, in no insignificant numbers, the height of 24,000 feet, while some ascend thousands of feet beyond that. In Mount Everest, of the Himalaya chain, the loftiest summit yet measured (29,000 feet) is found; although it may be that future investigations more to the south will disclose yet greater heights.

Highlands.

Continuous highlands or plateaus seldom attain an elevation greater than a half or a third of the loftiest mountains; the most elevated range in altitude, from 8000 to 12,000 feet above the sea level. On an average, they lie about 4000 to 5000 feet above the sea. We take the last height as a convenient point of demarkation between the two classes of highlands—those of the first and those of the second magnitude. It is an arbitrary point, of course, and the division there must remain, without a natural base to rest upon, till more results in Hypsometry shall have determined the real point of average between the combined lowlands and the combined highlands of the earth’s surface. Meantime this division will be of great service to us in enabling us to bring into a definite and appreciable classification many facts which would otherwise not be so well understood in their relations.

Highlands or Plateaus of the First Class.

By plateaus of the first class, we mean those high, continuous plains which lie at the elevation of more than from 4000 to 5000 feet above the sea level. The extreme height to which such plateaus rise is a fact yet to be ascertained. At an elevation of from 4000 to 5000 feet the highlands of the first class merge into those of the second. The point of transition is, of course, very difficult to fix with precision.