36 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 64 



Anomocare latelimbaturn Dames (35;! Limestone). 



Anomocare lisani Walcott (35g). 



Anomocare megalurus Dames (35M Limestone). 



Anomocare minus Dames (35M Limestone) (36^ Shale) (36/O. 



Anomocare minus Dames var. undt. (35n Limestone) (36c Shale). 



Anomocare subquadratum Dames (3Sn Limestone). 



Anomocarella chinensis Walcott (35n) (3Sr Limestone) (36g). 



Anomocarella hermias Walcott (3Sm Limestone). 



Anomocarella macar Walcott (35H Limestone). 



Anomocarella tcmenus Walcott (35?! Limestone) (35r). 



Dolichomctopus deois Walcott (350) (35/) Shale) (35?- Limestone). 



Bathyuriscus manchiiriensis Walcott (350) (36^) (36/2 Shale). 



Asaphisctis iddingsi Walcott (35r Limestone) (36^). 



GEOLOGICAL CONDITIONS 

 PRE-CAMBRIAN CONTINENTAL CONDITIONS 



The material composing the surface of the land that was await- 

 ing the advance of the Cambrian sea must have been, as described 

 by Willis, very largely made up of clays and sands resulting from 

 the long disintegration of the continental surface at a relatively low 

 relief. Applying this conclusion, we infer that the Asiatic continent 

 at the beginning of Cambrian time was practically a featureless con- 

 tinent and that the transgressing Cambrian sea gradually rose, 

 carrying with it the marine life that developed in the sea on the 

 continental slopes during the long period in which the pre-Cam- 

 brian continental surface had been worn down nearly to base-level. 



If we now turn to the life contained in the first series of deposits, 

 the Man-t'o formation, we find that it represents the closing epoch 

 of Lower Cambrian time that succeeded the faunas of the Olenelhis 

 epoch of the older western American formations, and the traces of 

 the Lower Cambrian fauna that have been found in Siberia. The 

 presence of a portion of the later Lower Cambrian fauna in Siberia 

 indicates that this portion of the Asiatic continent was at a lower 

 level and hence was traversed at an earlier epoch by the Cambrian 

 sea than the portions of southeastern and southern Asia, which in- 

 clude Manchuria, eastern and southern China, and northern India. 



The relations of the Cambrian strata to the subjacent rocks com- 

 pel the conclusion that the Asiatic continent was a land surface 

 during the earlier part of Cambrian time and during the long 

 Lipalian interval,^ represented by the deposition of the great series 

 of pre-Cambrian sedimentary rocks on the North American conti- 



' Walcott, C. D. Smithsonian Misc. Coll., Vol. 57, Cambrian Geology and 

 Paleontology, No. i, 1910, Abrupt appearance of the Cambrian fauna on the 

 North American continent, p. 14. 



