Sport and Science on the Sino-Mongolian Frontier

Geologically the country traversed on the various journeys described in this book may be divided into two sections, separated roughly one from the other by the outer loop of the Great Wall.

South of this line, in Chihli and Shansi, the outcrops are chiefly of sedimentary rocks, with here and there masses of the underlying plutonic and metamorphic rocks showing through. Thanks to Baron von Richthofen and Bailey Willis these rocks are pretty well understood, and there remains only the work of recording their occurrence in different localities, and any other geological phenomena hitherto unobserved. These stratified rocks extend westward and northward across the Ordos, North Shensi and well into Kansu, and also up to the extreme north-west of Shansi.