

30 RESEARCH IN CHINA. 



Sinian not far away, at Nan-t'ang-mei', and probably equivalent to the 

 Hu-t'o system, which is separated from the Sinian by a decided break. 

 Where it exists, the unconformity is everywhere taken as the dividing plane 

 and the equivalent horizon must elsewhere determine the limits of Cam- 

 brian upon pre-Cambrian, even though the strata be locally conformable. 

 Hence we are constrained to exclude from the Sinian certain limestones, 

 which von Richthofen regarded as "Untersinisch," but which in all prob- 

 ability represent deposits that are pre-Sinian. 



Thus used to name a series of conformable strata deposited during the 

 great Cambro-Ordovician transgression of Asia, the term Sinian has wide 

 correlative application, since a similar transgression spread over much of 

 North America and Europe and was there accompanied by evolution of 

 faunas closely related to those of Asia. From Cambrian to Ordovician 

 there is general continuity of physical conditions and faunal evolution. A 

 natural plane of division marked by unconformity frequently occurs near 

 the middle Ordovician. The strata below that plane to the base of the 

 Cambrian may be appropriately called Sinian.* 



Von Richthofen gives the following description of the Sinian in his 

 chapter on the rocks of Liau-tung :f 



The above-described stratigraphic fact [a marked unconformity of dip] sharply dis- 

 tinguishes the formations which have been described [pre-Cambrian metamorphic rocks 

 and intrusives] from a series of strata which we found to be widely distributed along 

 our route. In regular succession they follow one another. They everywhere exhibit a 

 richly varied stratification, which in the upper part is somewhat monotonous, but in the 

 lower shows many peculiarities in consequence of the fact that the strata, which were 

 deposited upon a sea bottom that was set with reefs, extend in some regions deeper than 

 in others. At a certain horizon which is high in the series we found globulitic limestones 

 that are especially distinct and afford a paleontological clue. According to a communica- 

 tion from Mr. Dames the trilobite fauna of Sai-ma-ki and the Tai-tsze valley consists 

 essentially of the genera Dikelocephalus and Conocephalus, and is closely related to the 

 fauna of the Potsdam sandstone of New York, Wisconsin, Iowa, and Minnesota, especially 

 the province of the upper Missouri, and the relation is such that there is indeed no doubt 

 of their equivalency. In the Fortieth Parallel survey the same fauna has been recognized 

 by Hah 1 in the mining districts of White Pine and Eureka. It seems that the Chinese fauna 

 more closely resembles the American Potsdam fauna than the Swedish Cambrian. It 

 has nothing in common with the Bohemian primordial fauna. 



It is not appropriate to apply the name Cambrian immediately to the formation under 

 discussion. For, until it may be possible to distinguish the paleontological horizon, we 

 are obliged to assign to it an extraordinarily long sequence of strata, which constitutes a 

 great whole in consequence of stratigraphic conformity, without any possibility of proving 

 that the beginning and end correspond with those limits within which the name Cambrian is 



*A. Geikie has translated the German terra "Sinisch" as "Sinisian." The original English form used 

 by the author of the name is "Sinian." 

 t China, vol. u, pp. 107-108. 



