"CERATOPS beds" OF WYOMING AND MONTANA 275 



a thin bed of mostly brackish-water shells, among which the following 

 have been identified from a locality in T. 22 N., R. 89 W.: 



Ostrea suhtrigonalis E. & S. 

 Ostrea glabra M. & H. 

 Anomia micronema Meek 

 Mytilus subarcnaius M. & H. ? 

 Corbicula occidentalis M. & H. 

 Mclania wyomingensis Meek? 

 Odontobasis buccinoides White 



Above the Mesaverde is the Lewis shale, about 1500 feet thick, 

 with some layers of concretionary sandstone which are often fossilif- 

 erous. In the township above-mentioned these yielded the following 

 marine fossils: 



Ostrea sp. 



Modiola galpiniafia (E. & S.) ? 



Avicula nebrascana E. & S. 



Syncyclonema rigida H. & M. 



Nucula sp. 



Protocardia subquadrata E. & S. 



Corbula sp. 



Dentalium gracile H. & M. 



Anchura sp. 



Baculites ovatus Say 



Scaphites nodosus Owen 



The same fauna, with some additional species, such as Avicula 

 fibrosa M. & H. and Lucina occidentalis (Morton) is also found in 

 calcareous concretions in the dark shales. 



The coal-bearing formation, about 3900 feet thick, conformably 

 overlying the Lewis, is called Laramie in Smith's report. Near the 

 middle of the formation in T. 22 N., R. 89 W., in line across the strike 

 from the Mesaverde and Lewis localities above recorded, Corbula 

 suhtrigonalis M. & H. was collected and 10 feet higher Tulotoma 

 thompsoni and Campeloma sp. occur. Fuller collections were obtained 

 from this formation from the adjoining township on the south. Here 

 a brackish- water bed about 1000 feet above the base yielded 



Ostrea glabra M. & H. 

 Ostrea siibtrigonalis E. & S. ? 

 Anomia micronema Meek 

 Mytilus subarcuatus M. & H. ? 



