250 EEPOET UNITED STATES GEOLOGICAL SUEVEY. 



5. Cardium suhcurtum Meek. 



See remarks under head of notes on Cretaceous fossils of Coalville. 



6. Cyrena securis Meek. 



See remarks under head of notes on Cretaceous fossils of Bear Eiver 

 Valley, and also on those of Coalville. 



7. Corhula duhiosa White. 



See notes on Cretaceous fossils of Bear Eiver Yalley. 



8. Neritina incomjyta White. 



Discovered only at this locality. It is described and figured in another 

 part of this volume. 



9. Turhonilla {Gliemnitziaf) coalvillensis Meek. 



See remarks under head of notes on Cretaceous fossils of Coalville. It 

 is described and figured in another part of this volume. 



A glance at these collections from Bear Eiver Yalley and near Hilliard 

 Station, in the valley of Sulphiu? Creek, the two localities being only 

 about four miles apart, shows that the Cretaceous invertebrate fauna 

 here, although much less fally represented, is essentially the same, and 

 quite as pecuMar as that of Coalville. In discussing the Coalville fossils 

 it was shown that we may exi)ect to find a similar Cretaceous fauna 

 south of the Uinta, and east of the Wasatch Mountains ; and it now 

 appears equally certain that we shall find that pecidiar fauna to extend 

 farther northward than the valley of Bear Eiver. 



In connection with the strata which are exposed along the valley of 

 Suli)hur Creek, a part only of which are represented in Mr. Meek's sec- 

 tion, there are some near Hilliard Station that appear to i)ossess the 

 peculiar characteristics of the Colorado Group, but which inclement 

 weather prevented me from iuA^estigating. If this supposition be cor- 

 rect, the strata coming in the series between them and those of the 

 Laramie Group of course belong to the consolidated Fox Hills Group. 

 As these strata here have an aggregate thickness of not less than 3,000 

 feet, it is probable that the whole fossdiferous series of Cretaceous rocks 

 at Coalville are referable to the same group ; especially so as, almost 

 without exception, the fossils of the Bear Eiver and Sulphur Creek 

 strata have been recognized in the Coalville series. 



While making the foregoing observations in the valleys of Bear Eiver 

 and Sulphur Creek, a fall of snow gave admonition of the approaching 

 close of the season, and I therefore then went eastward to Green Eiver, 

 crossing it at Green Eiver City. From there I passed up Bitter Creek, 

 a tributary of Green Eiver, and the weather being then favorable, I made 

 the observations upon the Laramie strata there, which have been re- 

 corded on preceding pages of this report. 



From Black Buttes Station eastward to Bitter Creek Station oiu- route 

 was over the strata of the Wasatch Group, the dip being gently to the 

 eastward, but becoming very slight or hardly perceptible in the neigh- 

 borhood of the last-named station. From this station our route was near 

 to and parallel with the Union Pacific Eailroad until we left the field at 

 Eawhns' Springs. As far east as Eed Desert Station our course seemed 

 to be directly upon the line of strike, and near or ui)on the division be- 

 tween the Wasatch and Green Eiver Groups. In this region as well as 

 at other places wheie I have examined these two groups near their junc- 

 tion, it is impossible to say where one ends and the other begins. This 

 is rendered still more difQcult by the fact that the best known of the niol- 

 luscan species of both gToups range from the Wasatch up into the Green 



