Page:Encyclopædia Britannica, Ninth Edition, v. 14.djvu/229

Rh are and the Desguadero in, and  and the  on the.

Distribution of Lakes.—Although there are few where lakes are entirely absent, still it requires little study to see that they are much more thickly grouped in some places than in others. Of the larger lakes, for instance, we have the remarkable group in, which together form the greatest extent of in the world. A similar group of immense lakes is found in :— and, whose overflow go to form the ; , at the source of the ; and , on a  to the. In the largest  lake is, on the upper  of the. All these lakes of great size are at the sources of large and important s; the  lakes in which  also abounds are at the  of large s, as the  at the  of the, and  at the  of the. Passing from the consideration of these larger lakes, which from their size may be considered inland s, and which therefore necessarily occur in small number, we find large numbers of lakes of comparatively small dimensions, and when we consider them attentively we find that they are reducible to a small number of, and, as in the case of and, the distribution of these is regulated chiefly by , but also by. Perhaps the most important and remarkable of lakes is that to which the  lakes belong. They are generally characterized by occupying long narrow depressions in the s of a ous in the neighbourhood of the, and in a. On the -coast, lakes of this character are found in, , , , the southern extremity of , and the south end of the middle of ; somewhat removed from the  we have the ine lakes of  and , and the great  lakes, all of which display the same features as those of  or of. In many flat countries lakes are extraordinarily abundant, as for instance in the north part of and, in the southern part of , in the northern parts of , and on a small scale in the. s, found on all low y coasts, owe their origin to the shifting of the under the influence of the and. They are found at the of large s, as on the  and at the  of the. In regions lakes are not uncommon, generally of a more or less, and either occupying the site of extinct s or due to subsidences consequent on eruptions; such are the  of the  in, and many lakes in  and in the. Lakes are not only widely distributed in and, they also occur at all s. Indeed, as a certain above the  produces an effect as regards  equivalent to a certain increase of, we find lakes existing in the centre of , and on high s and , in s where they would be speedily dried up if at the level of the. Many of the lakes in (as, , ), of , of , and of southern  are raised only by a few  above the level of the , and are separated from it often by only a few hundred  of , while in the  of  we have  12,500 , and in   10,500  above the. Many lakes whose surface is raised high above the level of the are so deep that their bottom reaches considerably below that level.

Dimensions of Lakes.—The principal measurements connected with a number of lakes in different parts of the, presented in the following table, will give a more precise idea of the size of the lakes than could be given by description alone:—

From this table it will be seen that by far the largest continuous sheet of is the group of n lakes, and of these is more than double the size of any of the others; this is principally due to its great breadth, as it is very little longer than. communicates with and, which are really branches of one and the same lake, by the , the  being 49  from  to. empties itself into by the , , and finally the. overflows by the  and  into, whence the  finally is conveyed to the  by the. The area of the lakes together is in round numbers 100,000, and, if that of the and its  be added, the  area will be about 150,000 , while the whole  area is only 537,000. Hence of the conveyed by the  to the, rather more than one-fourth falls on the surface of the  itself. Looking to their great extent, we should have suspected them to be much deeper than is found to be the case. The deepest,, is no deeper than in. Comparatively shallow, however, as they are, the bottoms of them all, with the exception of, are several hundred below the level of the. It has been supposed that in former times this chain of lakes formed an arm of the similar to the  in, and in support of this view we have the fact of the discovery of  in. In  is in every way comparable to the great  lakes as regards size. Its area of over 9000 makes it about equal to  in superficial extent, while its enormous depth of over 4000  makes the volume of its  almost equal to that of. Although its surface is 1360 above the -level, its bottom is 2720  below it. A former connexion with the has been claimed for this lake, owing to the fact that  inhabit its. Other large lakes in are mostly, and some lie wholly below the level of the. Thus the lies 85  below the, and the bottom at its greatest depth is 3000  deeper. The is over 1300  deep, and its surface is 1272  below the, so that its bottom is 2580  below the level of the sea. In the  are found. A former connexion with the has been claimed for the, but this 