342 Culver—The Erosive Action of Ice. 
the Italian geologists, that all that the glaciers as a whole 
effected was only slightly to deepen these valleys and to materi¬ 
ally modify their general outline, and, further (a theory for 
which I alone am responsible) to deepen them in parts more con¬ 
siderably, where, from various causes, the grinding power of 
the ice was unusually powerful, especially where, as in the low¬ 
lands of Switzerland, the Miocene strata are relatively soft. ” 
This is certainly a very conservative view in comparison with 
his published opinion of two years before. 
Dr. Falconer 2 attacked the views of Ramsay as to the origin 
of the alpine lakes and called attention to the mechanical diffi¬ 
culties which he thinks were quite overlooked by the followers 
of Ramsay. He referred to lake Maggiore, in which, after the 
ice has plunged down to the depth of nearly half a mile, it comes 
sliding up again at the rate of one hundred and eighty feet to 
the mile. 
He thought the lake basins in the Alps were caused by the 
upheaval of the mountains, that rivers ran into them and had 
begun to silt them up when the glaciers came and re-excavated 
them, and carried on past them the large drift deposits which 
would otherwise have filled them. 
In the Himalayas, on the southern slopes, the basins were 
thus filled and there there are no lakes, while on the northern 
slopes the ice extended farther and so carried the drift beyond the 
basins, and on that side lakes abound as in the Alps. 
There is food for thought in this latter suggestion, but it is not 
easy to see how the mechanical difficulties suggested in the case 
of lake Maggiore are any more easily overcome on Falconer’s 
hypothesis than on Ramsay’s. G-rant that the ice entered the 
basin and passed beyond it, and it makes no difference what 
agency formed the basin; the ice must “plunge” down and “slide 
up” just the same in either case. 
In 1869 Sir Archibald G-eikie read a paper before the Royal 
Society of Edinburgh, in which he maintained the glacial origin 
of the Swiss lakes, and dwelt upon the intimate connection be¬ 
tween the alpine lakes and the innumerable rock-basins of the 
northern hemisphere, intimating that these two are of glacial 
origin. In his Text-book of Geology, 2d ed., he maintains the 
2 Proc. Royal Geog. Soc., Jan., 1864. 
