APPENDIX A. 



SYSTEMATIC LIST OF FOSSILS FOUND AT EUREKA, NEVADA. 



BY CHARLES D. WALCOTT. 



In the monograph of Mr. Arnold Hague the grouping of the different genera 

 and species and their stratigraphical succession and relations throughout the great 

 thickness of sediments at Eureka are given with considerable detail in the discussion 

 of the Paleozoic, rocks. For the student of general geology the vertical range of 

 species and their geographical distribution are (dearly brought out. 



For the purpose of bringing together in tabulated form all the genera and 

 species of each important group into which the rocks have been divided, the following 

 systematic list was originally published in the Paleontology of the Eureka District, 1 

 and is reproduced here in order that the student may see at a glance the life of each 

 geological horizon. 



Invertebrate life is well represented throughout the entire series of rocks from 

 the base of the Prospect Mountain limestone to the summit of the Upper Coal- 

 measure limestone, a thickness of over 28,500 feet of sediments. 



In the list all the Cambrian fauna is included under the head of Prospect 

 Mountain group, embracing the Prospect Mountain limestone, Secret Canyon shale, 

 Hamburg limestone, and Hamburg shale. 



Since the publication of the Paleontology the Cambrian fauna has been divided 

 into three subfaunas: Lower, Middle, and Upper. Under this classification the 

 Lower Cambrian or OleneUiot fauna is included in the quartzites and immediately 

 superjaceut shales beneath the Prospect Mountain limestone; the Middle Cambrian 

 fauna in the Prospect Mountain limestone and Secret Canyon shales, and the Upper 

 Cambrian fauna in the Hamburg limestone and Hamburg shales. As the monograph 

 of Mr. Hague does not deal with these fauna! subdivisions in detail no further refer- 

 ence will be ma.de to them. 



A number of generic references will be chauged in a forthcoming review of the 

 Middle and Upper Cambrian faunas, but it is not thought best to anticipate these 

 changes in the present systematic list. 



1 Paleontology of the Eureka District, Nevada. Hon. XT. S. Gool. Surv., vol. vm, 18M. 



318 



