172 SMITHSONIAN MISCEI^LANEOUS COLLECTIONS VOL. 53 



There are many partial sections that supplement various portions 

 of the three great sections. These I wish to utilize in connection 

 with the study of the Cambrian trilobites of the Cordilleran area, as 

 our present knowledge of the vertical range and distribution of the 

 trilobites is too limited and inaccurate to be more than of value in 

 general and broad correlations. It is also true that many of the 

 great limestone beds now considered as almost without fossils will 

 be found in their extension away from the three great sections to 

 contain a well-marked fauna. 



In closing this brief review, I wish to call attention to the close 

 relationship between the great Cambrian section of the Province of 

 Shantung, China, and the Cordilleran sections. The thickness of 

 the strata is very much less, but the general character and strati- 

 graphic succession of the Cambrian faunas is very much the same. 

 This will be discussed in the introduction to a paper on the Cambrian 

 faunas of China, upon which I am now at work. 



