INTRODUCTION The materials described here in this paper were collected from three regions (1) in theOmeishan of Szechuan, (2) along the Szechuan-Kweichow border, and (3) in the central Yunnan.Collections from the former two regions were collected by the author in 1938-1940, while fromMr. C. S. Pien and the late Mr. T. Y. Hsu. The trilobite-bearing strata of these regions