GKOLOGICAI. RESEARCH IN EASTERN ASIA. 283 



Upper Cambrian. It contains few fossils, but enough were found 

 to demonstrate its Ordovician age. It is the counterpart of the 

 Shenandoah limestone of Virginia in lithologic character and in its 

 relation to the Cambrian series, and it thus appears that in eastern 

 Asia, as in eastern America, the passage from the Cambrian to the 

 Ordovician was without break in the sequence of strata or associated 

 faunas. This relation was not recognized by Baron von Richthofen, 

 who mistook the Ordovician limestone for the Carboniferous, which 

 it closely resembles. 



In southern Shensi, on the Ta-ning River, fossils of Cincinnatian 

 age were collected in abundance at a single locality, the only one in 

 which the terrane was teen. No previous record of the occurrence 

 of strata of this age in China is known to me. 



Carbonijeroics Strata. — The contribution to knowledge in reference 

 to the Carboniferous is a correction of former views. In southern 

 China there is a conspicuous Carboniferous limestone ; in southern 

 and northern China there is a similar limestone of Ordovician 

 age. Baron von Richthofen, not recognizing the distinction, mapped 

 the Ordovician of northern China as Carboniferous, but it is now 

 possible to indicate correctly the limits within which the Carbon- 

 iferous occurs, so far as our observations go. 



Connected with the preceding is the recognition of an extensive 

 unconformity between the Ordovician and the Coal Measures 

 throughout northern China. 



CONTRIBUTIONS TO GEOI.OGV OF THH PRE-CAMBRIAN. 



Basement Complex. — The occurrence in Asia of ancient crystalline 

 schists and intrusive igneous rock, constituting a basement complex 

 beneath the obviously stratified series, has long been known through 

 the work of Baron von Richthofen and of Russian explorers. The 

 present contribution to knowledge of the system consists of more 

 detailed observations of the relations of its members — several kinds 

 of schists, gneiss, granite, and basic intrusives. One area, the 

 Tai-shan in Shantung, was somewhat closely studied, and from it as 

 well as from widely separated localities in Chihli, Shansi, and Shensi, 

 specimens were secured for petrographic investigation. 



P)x-Camb}ia7i Sedimentary Series. — The Wutai-shan and adjacent 

 mountains in northern Shansi consist of rocks ranging in age from 

 the extremely ancient basement complex to the Coal Measures. 

 Between the complex and the base of the Cambrian are two series, 

 both of which were described by Baron von Richthofen, the older 

 as the " Wutai schist," the younger as the " Lower Sinian." In 



