OF LAKE-BASINS. 651 



remarkable point in the case, that this glacier, by the hypothesis, should 

 have plougfted its way down, and actually dived into the bowels of the 

 earth 2,000 feet below the level of the Mediterranean, and then should 

 have again risen up along an incline at a rate of about 180 feet per 

 mile. 



Without going into all the objections, he might state he believed the 

 principal one was, that the mechanical difficulties in the case were en- 

 tirely left out of sight by the supporters of that theory ; and on that oc- 

 casion, after very long study of the subject, he had endeavoured to bring 

 forward what occurred to him as the true explanation of the difference 

 between the Himalayan Mountains and the Alps. The difference he 

 believed to consist in this : that after the last upheaval of the Alps, 

 great fissures, or basins of lakes, were left there, with rivers running 

 into them, in the manner in which* the Rhone runs into the lake of 

 Geneva, bringing down vast quantities of silt, which, if you give a 

 sufficient number of ages, would have completely filled them up. But 

 before this was accomplished, what is called the Glacial period set in ; 

 that is to say, there was an enormous projection of ice and snow, below 

 the limit that they now saw it in the Alps, out into the plains, both to 

 the north and south of that chain ; and, as the snow and ice came down, 

 they filled up those lakes, and formed a bridge, upon which the moraine 

 material was carried over, there being a certain measure of incline from 

 the summit of the Alps down to the plains of Italy When once the 

 basins were filled with ice to the depth of 2,500 feet, they made, as it 

 were, a slide or incline, upon which all the solid material could be 

 transported ; and that being carried forward by the vis motrix of the 

 mass, formed the large moraine which we saw at Lake Maggiore, that 

 of the Brianza, and also the moraine which bounded Lake Garda, where 

 the battle of Solferino was fought. This was the secondary condition 

 that occurred in Europe. Precisely the same primary conditions oc- 

 curred in the great valleys of the Himalayahs, but without the same 

 glacial phenomena. These mountains were thrown up above the level 

 of the sea, and vast "perpendicular fissures left, forming what constituted 

 at that time the basins of lakes. But in those tropical regions, the ice 

 never descended from the highest summits down into the plains of 

 India ; and instead of being filled up by snow, which afterwards melted 

 into water, these lake basins were gradually silted up by enormous 

 boulders and alluvium of every kind, which were transported down 

 from the Himalayan Mountains in prodigious quantities by the torrential 

 action of the periodical rains. The difference in the two cases was, 

 that whereas the ice filled up the lake basins in the Alps, constituting, 

 as it were, the conservative means by which those basins were saved 

 from being silted up by alluvial and other matters, in the Himalayan 

 Mountains this conservative action did not take place, and the lake 

 basins remaining open got filled up in the manner above described. 

 If they would look at the map of the Himalayahs, one of the most 

 remarkable things they would observe on the southern side of the 

 chain was, that there were no great lakes whatever — not one that 

 would compare with Lake Lugano, or with any of the second or third- 

 rate lakes in the Alps. But if they crossed to the northern side of the 

 chain where the temperature was much colder during the winter, there 

 they would find great lakes. The cold produced the same conservative 



