CHARACTERISTICS AND DISTRIBUTION OF LAKES 573 
in geologically recent times, advancing to the south and south- 
eastward, leaving the land in the Scandinavian peninsula and Finland 
dotted with lakes, similar in origin to those nortlx of the lake-belt in 
North America, and creating a new land-surface in the northern plain 
of Germany by covering it with glacial deposit. The ice- sheet 
reached to the base of the Thuringian Forest, Erzgebirge, Sudetes, 
and Northern Carpathians. On the southern side of the Alps an 
independent sheet of glacier-ice passed down the valleys, and deposited 
terminal moraines far out in the valley of the Po. On the northern 
side the ice spread across the whole of the middle plateau of Switzer- 
land, at least half-way across the range of the Jura, and far eastward 
to the neighbourhood of Linz on the Danube ; while to the west a 
glacier passed down the Rhone valley, and deposited a great terminal 
moraine where Lyons now stands. Among the most important 
evidences of this ice-era are extensive morainic deposits, either in the 
form of bottom moraines or terminal moraines. Such deposits 
abound mostly where the ice-sheets were beginning to thin out, as in 
the North German lake-plateau, and numerous lake-basins have been 
formed by inequalities in the deposition of such morainic matter. 
These lakes are generally of small size, and occupy either circular 
depressions, long narrow basins, or broad shallow basins, very 
irregular in outline, lying in gently undulating ground. 
The most important lakes in England are those of the Lake England. 
District in Cumberland, all of which are valley lakes and occur at 
a comparatively low level. They were bathymetrically surveyed by 
Dr H. R. Mill and others in the years 1893 and 1894.i 
The lakes of the English Lake District may be divided into two 
main types : the shallow and the deep. The former type includes 
only Derwentwater and Bassenthwaite Water, of which the average 
depth is only 1 8 feet. The latter type, the shallowest of which has a 
mean depth of 40 feet (Haweswater), comprises all the other lakes. 
The fact that Derwentwater and Bassenthwaite are separated by an 
alluvial plain so low that their waters mingle in heavy floods shows 
that they may be regarded as one lake, and their configuration suggests 
that they may have been shallowed by glacial accumulations. Both 
are drained by the Derwent River, which enters the Solway Firth at 
Workington. 
Derwentwater is a little over 2 square miles in area, nearly 
3 miles in length, and has a maximum depth of 72 feet and a mean 
depth of only 18 feet. It lies at an elevation of 244 feet above sea- 
level, but this figure was given for 1893, when the level of the lake 
1 See Mill, " Batliymetrical Survey of the English Lakes," Geogr. Journ., vol. vi. 
pp. 46, 135, 1895. 
