200 Tne American Geologist. October, is96 
often with calcite seams, and the masses weather with an 
umber brown surface. 
1 Limestone : carrying shell remains. 
700 Series of alternating light colored sandstones and gray shale, 
like that above. 
5 Shales ; carrying fresh -water fossils. 
714 Series of alternating sandstones and shales, similar to those 
noted above. 
5 Lignite seam ; several other impure seams occur in 100 feet of 
beds above. 
27 Shales and sandstones. 
4 Sandstone : containing fresh-water fossils. 
10 Gray shales. 
2 Lignite seam. 
635 Series of beds of sandstones alternating with gray argillaceous 
shales of varying nature. 
5 Limestone ; containing fossils. 
900 Sandstones of varying texture, carrying occasional beds of 
limestone. 
7136 Livingston formation ; dark colored conglomerates, grits, sand- 
stones and tuffs, with interbedded tufaceous shales, all com- 
posed largely of volcanic debris. 
1080 Laramie formation ; sandstones, buff and gray, with interbed- 
ded shale. 
500 Fort Pierre shales, and Fox Hills sandstone. 
The importance of this section, which is the only one knovk^n 
to the writer in which the Fox Hills, Laramie, Livingston and 
Fort Union formations occur superimposed, is apparent when 
it is considered that in eastern Montana and Canada the Fort 
Union rests directly upon Laramie beds in apparently perfect 
conformity. 
The invertebrate remains from the beds noted in the section 
just given are all fresh-water forms. They have been deter- 
mined for me by T. W. Stanton, who reports the following 
species : 
Viviparus trochiformis M. & H. 
V. retusus ? 
V. leai ? 
Bulinus longiusculus ? M. & H. 
B. subelongata M. & H. 
Campeloma multilineata M. & H. 
Valvata subumbilicata M. & H. 
Goniobasis tenuicarinata M. & H. 
Unio priscus ? M. & H. 
U. couesii. 
U. dana? ? M. & H. 
U. primajvus. 
Of this fauna, Mr. Stanton says:* 
*Mss. Official Report to Director of U. S.G.S., upon request of writer. 
