330 W. II. WEED TWO MONTANA COAL FIELDS. 



and is cross-bedded and pitted. It shows poorly preserved leaf remains. 

 Fossil leaf remains occur in a Letter state of preservation in the sand- 

 stones between numbers iv and v, where they have been quarried for 

 building purposes. A collection made by the writer has been studied 

 by Mr. V. H. Knowlton, who reports the species to present a decidedly 

 Fort Union fades. 



The remains of Unio obtained from the roof of scam number iv have 

 been examined by Dr. C. A. White, who reports them to belong to two 

 species, Unio senectas, White, and Unio dmifr, M. A* H. These species are 

 of too widespread occurrence in the fresh-water Cretaceous rocks to fix 

 any definite horizon. 



In the lack of definite structural evidence of the age of the coal meas- 

 ures, we must therefore rely upon the plant remains. These are of Fort 

 Union types and belong to a flora quite distinct, so far as studied, from 

 that of the true Laramie, or that of the Livingston beds of the Bozeman 

 coal field farther westward. 



