i2 4 THE POPULAR SCIENCE MONTHLY 



confines of India there extends a series of high mountain ranges sepa- 

 rated by deep and narrow valleys, all trending in a south or south- 

 easterly direction. Although not so high above sea-level as the moun- 

 tains north and south of Thibet, these ranges are an even more effective 

 barrier to travel because they are so continuous and the relief is so 

 great. Not only is there no waterway, but there are no wagon roads, 

 and the building of a railroad would be a stupendous and expensive 

 engineering task. Such a road would necessarily involve the making 

 of a succession of long bridges and tunnels. Here, as in the Central 

 Eanges, settlements are limited to the rare open spots in the bottoms 

 of valleys, and so the population is sparse indeed. The total commerce 

 is very small in volume, because goods must be carried almost entirely 

 on the backs of coolies. The rugged characteristics of the region are 

 evidently the direct result of the recency of the compressive movement 

 which produced the tremendous mountain folds, and perhaps are still 

 more due to the renewed uplifts which have permitted the streams to 

 continue the carving of their deep gorges. This part of China is geo- 

 logically very young, and to quote the words of the distinguished old 

 geologist of California, Joseph LeConte, " the wildness of youth (here) 

 has not yet been tempered by the mellowness of age." 



