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 



MAP SHOWING THE COURSE OF THE ANCIENT GLACIER OF THE RHONE, AND THE PISTRIBUTION 

 OF ERRATIC BLOCKS ON THE JURA. 



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 



