THE ARKANSAS COAL MEASURES. 1 99 



U. S. Geological Survey, from the Eureka district, Nevada, where 

 a Waverly fauna occurs 3000 feet above the base of the Carbon- 

 iferous formation. The same thing has been observed by the 

 writer in the Carboniferous of Shasta county, California. 



The Lower Carboniferous limestones can be traced all 

 through the west and the Mississippi Valley, to the base of the 

 Appalachian Mountains, where they are replaced by conglomer- 

 ates and other coarse sediments. 



Upper Carbonifero7is in the West. — Of the Upper Carboniferous 

 all that we know west of Indian Territory takes on a decidedly 

 marine character, containing thick beds of limestones. 



There are however some thin beds of coal in Texas, and 

 some carbonaceous seams with a few land plants in New Mexico 

 and Nevada. The coal in Texas was probably deposited near 

 the southern shore line of the Carboniferous sea, and the carbon- 

 aceous seams in the far west probably belong to insular areas. 



The fossils described from the Western Carboniferous are all 

 marine, with the slight exception that Walcott^ mentions a few 

 specimens of pulmonate Gasteropoda, that were found along with 

 brachiopods, corals, and land plants, evidently washed in from a 

 distance, since no terrestrial Carboniferous deposits are known 

 near the Eureka district. 



The Patvhuski limestone. — In the eastern part of Indian Terri- 

 tory are found large deposits of coal in the Upper Coal Measures, 

 but further west the same horizon is represented by marine lime- 

 stone. In 1892 Mr. H. C. Hoover, of the Geological Survey of 

 Arkansas, found at the government lime-kiln, three miles north- 

 west of Pawhuski, Oklahoma Territory, Osage Agency, a bed of 

 massive limestone about lOO feet thick, lying horizontally on 

 heavily bedded sandstones. The limestone is fossiliferous, but 

 the sandstones are not. The fossils collected were placed at my 

 disposal, and on examination they proved to be : 



Spirifer cameratus Morton. 



Athyris subtilita Hall sp. 



Productus s entire tictdatus Martin sp. 



'Mon. VIII., U. S. Geol. Survey, p. 262. 



