REPORT ON PALMOTSfTQIA 



several of the tributaries of Weber Ri 

 at these localities in whitish and ligh 

 Ammia, an Oyster like 0. f/lahra, Meek 

 western species usually referred to J. jn 



fossils.* 









Cretaceous fossils were 



also co 







above Fort Laramie. They 



are Osti 



ra naujt 



sta, ( ! 



ramus, with fragments of a si 



nail Ban 



i/itcs, an 



docc 



of the ao-e of No. 2 or 3 or" 



the Y W 



er Miss, 



mri ( ' 



There are, likewise, in 





ection ; 



i few 



also differs from the other in being clearly an estuary or brackish- water deposit; while 

 the newer, so far as known, contains the remains of only strictly fresh-water mollusks. 



The older formation mentioned above was seen on Bear River, near the mouth of 

 Sulphur Creek, some 30 miles west of Fort Bridger, and but a few hundred yards 

 distant from the outcrops of brown coal and yellow sandstone with Titan ramus 

 already mentioned. These beds are chiefly dark-colored and grayish, argillaceous 

 shales, with coarse, dark and lighter-colored calcareous grits. The fossils found in 

 them belong to the genera Unto, Oorbula, Goniohusis, I'h'qmrus, and Tihytophorus ;f being- 

 just such an assemblage as we might expect to find in an estuary or brackish- water 

 deposit. 



The fossils from this region, figured by Professor Hall in Fremont's report, Plate 

 III, are fresh- and brackish-water types, and possibly may be from this horizon. I 

 have always been at a loss, however, to identify, with confidence, the species described 

 in Fremont's report, partly on account of the brevity of the descriptions and the want 

 of more satisfactory illustrations, but also to a great extent owing to the fact that the 

 localities are only given by longitudes and latitudes, which were, at that time, not 

 determined with sufficient precision to know certainly exactly from which one of 

 several distinct formations the specimens were obta ined. At one time I wa> rather 



- Since these remarks were written, I have visited this locality ."and found the ro : .l-l,,d> Uiere . • 



United States Geological Survey of the Territories, 1872.) 



tThe type of the genus Ehytophorua was originally ordered by me to Melampaa. 



