"CERATOPS beds" OF WYOMING AND MONTANA 269 



the Colorado shale and the Fort Union that have been used as for- 

 mations in Montana, because both the Claggett and the Bearpaw as 

 marine formations are either very thin or entirely represented by non- 

 marine deposits. The geology has been described by Fisher^" who 

 did not attempt to classify these higher rocks and brief abstracts of 

 the more detailed work by Woodruff^^ and Washburne*" have been 

 published. 



In the Shoshone River section below Cody there is a conglomerate 

 which is comparable in many respects with the Kingsbury. The 

 basal bed exposed at the mouth of Sage Creek contains many pebbles 

 of igneous rock, abundant rounded fragments of silicified wood and 

 many pebbles that look like the underlying Cretaceous rocks. Fort 

 Union plants identified by Doctor Knowlton were obtained from beds in- 

 tercalated in the conglomerates, as well as above them, and they range 

 down some distance below their base. The presence of the "Ceratops 

 beds" is indicated at several localities in the Basin by fragmentary 

 dinosaur bones and by a few fresh-water invertebrates which are 

 usually associated with them, though nothing strictly distinctive has 

 been found among the invertebrates. In every case the dinosaurs were 

 found in beds lower than the lowest recognized Fort Union plants. 



Similar stratigraphic relations are found just north of Bighorn 

 Basin near Belfry and between Bridger and Red Lodge, Montana, 

 except that the marine formations are recognizable and the Fort Union 

 is much thicker and contains many workable coals. Dinosaur bones 

 are found in the part of the section designated as "Laramie" in 

 Woodruff's*' sketch and associated with them are the following inverte- 

 brates: 



Unio sp. Related to U. brachyopisthus White 



U. pyramidatoides Whitfi.eld? 



U. cylindricoides Whitfield? 



U. verrucosiformis Whitf. 



SphcBrium 



Physa 



'* Fisher, C. A. : Geology and Water Resources of the Bighorn Basin, "Wyo- 

 ming, Professional Paper, U. S. Geo!. Survey, No. 53, 1906. 



^'Woodruff, E. G. : Coalfields of the southwest side of the Bighorn Basin, 

 Wyoming, Bull. U. S. Geol. Survey, No. 341, p. 200-219. 



*" Washburne, C. W. : Coalfields of the northeast side of the Bighorn Basin, 

 Wyoming, Idem., pp. 165-199. 



" Bull. U. S. Geol. Survey, No. 341, p. 96. 



