586 THE FRESH-WATER LOCHS OF SCOTLAND 
numerous littoral and bottom forms. More than one thousand 
species of plants and animals are noted, the numbers being approxi- 
mately equal. 
Lake Ferto (or Neusiedler See), in the extreme west of Hungary, 
370 feet above sea-level, is so extreniely shallow (maximum depth 
13 feet, mean depth not averaging 3 feet) that it sometimes evapor- 
ates completely in very dry years, as it did in 1865. It is refilled 
by the waters of the Danube when the river rises sufficiently high to 
force back the sluggish stream of the Hansag, which communicates 
with Lake Ferto through the Hansag swamp on the east, now for 
the most part under cultivation. The lake is 18 miles in length, 
by from 4 to 7 miles in breadth, and sometimes attains an area of 
130 square miles. 
Lake St Moritz, etc. — The River Inn, a tributary of the Danube 
rising in Switzerland, has a chain of lakes near its source, viz. Lake 
St Moritz, Lake Campfer, Lake Silva Plana, and Lake Sils, which 
have been referred to as typical illustrations of the lakes sometimes 
associated with river capture. The upper portion of the Engadine, 
the valley of the Inn, is of such a breadth as would appear to 
indicate a great river, the source of which must be miles away.^ 
Instead of this there flows through the valley a small stream with a 
succession of lakes threaded on it. At Maloja the valley itself, 
still broad and deep, suddenly ends with a steep descent into the Val 
Bregaglia, through which the River Maira flows. The slope of the 
Val Bregaglia being much steeper than that of the Inn, the River 
Maira gradually cut its way back, and appropriated more and more 
of the territory which once belonged to the Inn. The Val Marozzo, 
now called the Upper Maira, and the Val Albigna were once 
tributaries of the original Upper Inn, but have been carried off* into 
Italy by the victorious Maira. Hence the Upper Engadine is from 
the first a broad valley, because it represents part of the course of a 
stream which has lost its head- waters. Before this change the flow 
of water down the main valley was sufficient to carry off" the materials 
brought down by the lateral tributaries, but, since the head- waters 
have been cut off and carried away into Italy, this is no longer the 
case ; hence the lateral streams have built up dams across the valley, 
thus creating a chain of lakes. Johnson,^ on the other hand, says 
there is reason to believe that the lakes occupy basins of glacial 
origin. The three lakes Campfer, Silva Plana, and Sils formerly 
constituted a single body of water which was ultimately divided by 
the growth of deltas deposited by side streams, and Lake Sils is at 
^ Lubbock, Scenery of Sivitzeiiand, p. 453, London, 1896. 
2 D. W. Johnson, "Hanging Valleys," Bull. Amer. Geogr. Soc, vol. xli. p. 665, 
1909. 
