INTRODUCTION The observations presented here were made during a rapid reconnaissance expedition in Sikang Province (Chinese Tibet), organized in 1930 with the support of Sunyatsen University, Canton, A year previously, Rev. J. H. Edgar, of Tatsienlu, remarked that, as the result of attempts to trace the fissure-lines across the stricken area, he had become convinced that many of the fissures were of considerably greater age but had passed unnoticed until the time of the catastrophe. The accuracy of his conclusion was amply demonstrated during the course of the expedition, which greatly profited by his guidance in the field. Cordial thanks are due to him, as well as to Mr. and Mrs. Marcel Urech, of the China Inland Mission at Tatsienlu, whose hospitality and help were large factors in the success of the expedition. The most important publications dealing with earthquakes in China refer almost exclusively to North and Northwest China . . .