1882 *] 
335 
[Davis. 
In the Eifel and in Auvergne there are some small lakes of 
this species; in the former, the Schalkenmehrener, Meerfelder 
and Walsdorfer Maare *; in the latter, the Lacs des Bordes, de 
l’Eclouze, de Bourdouze, etc. 2 
A. 7. Subsidence Basins from Solution. V olcanic eruption o f 
the previous species may be replaced by removal in solution of 
more soluble strata, as salt, gypsum or limestone, below a less sol- 
uble surface covering. As the dissolved rocks are carried away, 
a depression is formed on the surface, and may hold a lake. 
Certain small, shallow meres in the Red Marl of Cheshire have 
long been explained in this way, as the strata there contain much 
salt. 3 Similar sinking of the ground explains the small basins in 
the salt region of Eisleben, over gypsum rocks by Berlin and 
by Segeberg in Holstein, 4 and over limestone in many parts 
of the world. The latter are very common in a small way; 
they often vary with the season from full capacity to dry- 
ness, and their outlet is generally through the bottom by under- 
ground streams. In this country they are commonly known as 
sink-holes ; in Ireland as sluggys, swallow-holes and turloughs. 5 
B. Destruction Basins include only those species in which 
erosion or excavation of some kind is sufficient to provide a hollow 
for a lake. As will be seen under the third class, this limitation 
excludes many species in which destructive agents have formed a 
trough, but where some supplementary action is necessary before 
a basin is completed ; hence runffing water is not found as a cause 
under this division. 
It is but recently that this has been fully recognized, as may be 
seen by examining the writings of geologists of the first half of 
this century. 6 Desor, the latest advocate of running water that I 
have found, thinks that many of the Swiss lakes were eroded 
by a powerful flood suddenly rushing out from the Alps and 
1 H. v. Dechen, Rheinl. u. Westph. Ges. Verh., xvm, 1861, 167. 
2 A. v.Lasaulx. Niederrhein Ges. Sitzungsb., xxv, 1868, 58. 
3 Hull, On the recent remarkable Subsidence of the Ground in the Salt District of 
Cheshire, Ireland Geol. Soc. Journ., vi, 1880-81, 87-92. See Ordnance Survey Eng- 
land and Wales, sheet 80. See also B. 3. 
4 Peschel, Phys. Erdk., ii, 324. 
6 Kinahan, Valleys, 141. 
6 For Example, Rogers, Geol. Penna., i, 39, On the Lakes in Central New York. 
