524 THE FRESH-WATER LOCHS OF SCOTLAND 
ultimately formed. A similar process produces lakes along continental 
shores through the formation of sand-dunes or accumulation of 
shingle, as, for instance, in Florida. 
4. Wind-formed Basins. — The wind travelhng in a cyclonic 
manner across plains often lifts the sand and earth, carrying them 
away, and thus forming shallow basins. Many of the shallow lake- 
pans of desert regions are believed to have been formed in this way, 
as well as lakes where sand-dunes are numerous.^ 
When a quite comprehensive view is taken of the land-surfaces of 
the globe, two regions may be distinguished : 
Two distinct (A) The region of inland drainage areas, where evaporation 
Lake Regions, g^cceds precipitation, situated in the desert regions of the globe. 
(B) The region of drainage areas, the waters from which 
FLOW directly INTO THE OCEAN, whcrc prccipitatioii exceeds evapora- 
tion, situated in the well- watered regions of the globe with abundant 
vegetation. The water of lakes associated with the former class (A) 
may be either salt or fresh ; that of lakes associated with the latter 
class (B) is always fresh. 
In reviewino; the distribution of lakes over the surface of the 
globe the order here suggested will be adopted in this paper. 
LAKES CONNECTED WITH INLAND DRAINAGE AREAS 
Distribution The inland drainage areas are situated in two belts running right 
draina^e^ round the world, the one in the northern hemisphere, approximately 
areas. between the latitudes of 30° and 50° North, the other in the southern 
hemisphere, approximately between the latitudes of 20° and 30° 
South. These regions correspond so closely with the great desert 
regions and with the salt-lake areas, w^here there is an annual 
rainfall of less than 10 inches, that the relation is evidently one of 
cause and effect. In the northern belt are the lakes of the Gobi 
Desert, the Sea of Aral, the Caspian Sea, the Dead Sea, the arid 
desert of Arabia, the lakes of the Sahara Desert, and of the Great 
Salt Lake and Alkali Deserts of the Rocky Mountains in North 
America. In the southern belt are the arid regions of the interior 
1 Sir John Lubbock, in his book The Scenery of Switzerland, p. 203, divides the 
lakes into the following four classes : — 
(1) Lakes of embankment. 
(2) Lakes of excavation. 
(3) Lakes of subsidence. 
(4) Crater lakes. 
In the year 1883 Professor W. M. Davis published a classification of lakes 
according as they were made by constructive, destructive, or obstructive processes 
(see Proc. Boston Soc. Nat. Hist., vol. xxi. p. 315, 1883). 
