3fesozoi€ and Ccenozoic Geology and Palaeonfology. 109 



Recurring to the Rocks at Coalville, he says: As I have, however, 

 mentioned faults and lateral displacements of the strata here, it ma.y 

 the thought, by some, who are yet incredulous in regard to the Cretace- 

 ous age of these coals, that these disturbances of the strata may have 

 given origin to erroneous conclusions respecting the position of 

 the beds containing the Cretaceous types with relation to the coals. 

 This, however, is simply impossible, because these fossils occur both 

 above and below the coal-beds, even in local exposures, where all the 

 strata, and included coal-beds can be clearly seen conformable and in 

 1 heir natural positions with relation to each other. We found both 

 above and below the main coal-bed, Inoceramus probleniatms^ a 

 widely distributed species, that is verj' characteristic of the Niobrara and 

 Benton Groups of the Upper Missouri, which there occup}^ positions 

 below the middle of the series. Again, far above this, numerous speci- 

 mens of a larger Inoceramus, which, if not reall}^ identical with one of 

 these forms, is scarceh- distinguishable from I. sagensis and /. nebras- 

 censis, which occur in the later members of the Upper Missouri series. 

 From these facts, it is more probable that we have here, at and near 

 Coalville, representatives of the whole Upper Missouri series, with pos- 

 sibly' even lower members, farther up Weber river, than anj' of the 

 known Upper Missouri subdivisions of the Cretaceous. If this is so — - 

 and there seems to be but little reason to doubt it — the marked differ- 

 ence observed between almost the whole group of fossils found here, 

 and those of the Upper Missouri Cretaceous, would seem to indicate, 

 that there was no direct communication between the Cretaceous seas 

 or gulfs of that region and those in which these Utah beds were de- 

 posited. Differences of physical conditions, however, probably also 

 played an important part in the production of this diversit}'- of life, 

 since it is evident from the great predominance of clays and other fine 

 materials in the Cretaceous beds of the Upper Missouri, that the}' 

 were deposited in comparatively deeper and more quiet waters than 

 those in Utah, in which coarse sandstones, with occasional pebbly beds, 

 predominate. 



The strata including the beds of coal exposed on Sulphur creek. 



