07Z C. SCHUCHEET PALEOGEOGEAPHY OF XOETH AMEEICA 



rial" are estimated by Diller to have 1,000 feet of thickness. Near the 

 United States Fishery Station, on the McCloud river, is found an abun- 

 dance of fossils, a good collection of which is now in the IT. S. National 

 Museum. They occur in the upper 150 feet of the Baird, and were pro- 

 visionally identified about fifteen years ago by the writer. The fauna may 

 be known as the Pro ductus giganteus. Some of the more characteristic 

 forms are : Productus giganteus (not typical with the European species of 

 Martin), P. punctatus, P. semireticuiatus, Cleiotliyridina roysii ?, large 

 Camaroplioria, Rhipidomella corallina (Waagen), Belhrophon cf. ste- 

 vensanus, Pleurotomaria cf. newportensis, and carbonaria, P. cf. subsin- 

 uata, Bulimorpha nitidula, Aviculopecten intcrlineatus, Streblopteria, 

 Lima retifera, Edmondia cf. aspinwallensis, Pleurophorus (3 species), and 

 Allorisma. 



From the foregoing list it may be seen that the fauna has a decided 

 Pennsylvanic aspect and that some of the species are also found in the 

 Mississippi valley. Associated with these are forms clearly of Asiatic 

 origin, which become more common in the higher beds. As there is prac- 

 tically nothing in this fauna resembling that of the Tennesseic, it is here 

 regarded as of early Pennsylvanic time, and is probably the equivalent of 

 the Lower Pottsville of the Appalachian and Mississippian seas. Smith 210 

 refers the horizon to the Lower Carboniferous, and identifies in it (in all 

 probability erroneously) Mississippic, Tennesseic, and Pennsylvanic 

 forms. The Russian geologists refer their Productus giganteus zone to 

 the Lower Carboniferous, which they correlate with the Belgian Viseian. 



Daly has collected and Ami has identified Productus giganteus in the 

 Flathead river region of southwestern British Columbia. In southeastern 

 Alaska, on Chichagof island, at Freshwater bay, Kindle has found the 

 same species. From these occurrences it is seen that this fauna is wide- 

 spread along the Pacific coast, but thus far it is not reported from the 

 Arctic regions, although Spirifer mosquensis of the next higher zone is 

 said to occur there. According to G. M. Dawson, 211 this and the later 

 Pennsylvanic sediments are widely distributed in British Columbia, and 

 are "mingled with contemporaneous volcanic materials, . . . tran- 

 quil epochs being marked by the intercalation of occasional limestone 

 beds." 



Above the Baird shales follows the McCloud limestone, said by Diller 

 to vary between 200 and 2,000 feet in thickness. At the base is found the 

 Omplialotrochus whitneyi fauna in part described by Meek in the Califor- 

 nia Report. Besides this large gastropod, there is an abundance of the 



210 Smith : Journal of Geology, 1894, pp. 594-599. 



2ri Dawson : Bull. Geological Society of America, vol. 12, 1901, p. 85. 



