CHAP. VII.] 
THE GLACIAL EPOCH. 
107 
remarkable examples of such travelled blocks are to be found on 
the southern slopes of the Jura. These consist of enormous 
angular blocks of granite, gneiss, and other crystalline rocks, 
quite foreign to the Jura mountains, but exactly agreeing with 
those of the Alpine range fifty miles away across the great 
central valley of Switzerland. One of the largest of these blocks 
is forty feet diameter, and is situated 900 feet above the level of 
the Lake of Neufchatel. These blocks have been proved by 
Swiss geologists to have been brought by the ancient glacier of 
the Rhone which was fed by the whole Alpine range from Mont 
Blanc to the Furka Pass. This glacier must have been many 
thousand feet thick at the mouth of the Rhone valley near the 
