2l6 KNOWLTON 



is perhaps a sufficient excuse for omitting their further consideration 

 until additional information, both paleobotanical and stratigraphic, 

 is at hand. 



To the eastward of Black Buttes, in the vicinity of Creston, Riner 

 and Rawlins, and as far at least as the vicinity of Carbon, Fort 

 Union plants and occasional dinosaurs have been found. The beds 

 containing them belong to the so-called "upper Laramie" of Veatch 

 and others, that is above the unconformity at the top of the Laramie, 

 but whether or not this series of beds is a unit is an open question 

 at present. It seems probable to the writer that the lower portion 

 may belong to the recently established Shoshone group of Cross, 

 and the upper portion only to the Fort Union. To the west in the 

 vicinity of Evanston a few Fort Union species have been noted, but 

 in all these cases further data are demanded. 



Relations Between the Lower Member of the Fort Union 

 AND Underlying Formations. 



Having traced the areal distribution of what is here called the 

 lower member of the Fort Union formation, as completely as present 

 facts seem to warrant a brief recapitulation of the relations that have 

 been demonstrated of these to the underlying beds may be made. 

 In the Hell Creek region of Montana, the vicinity of Yule, North 

 Dakota, and on Alkali Creek, Weston County, Wyoming, the beds 

 rest unconformahly on the Fox Hills. At Forsyth, near Custer, 

 the areas south and east of the Bull Mountains, and probably at 

 Glendive, all in Montana, and at Buffalo, Wyoming, the beds rest 

 directly on the Pierre, and not always its uppermost member. In 

 Converse County, Wyoming, the basal conditions are not definitely 

 known, though presumably the relations may be similar to those 

 obtaining in adjacent Weston County. Throughout the Great 

 Plains area the Fox Hills is usually, but not always present, and even 

 when present has not always been satisfactorily separated from the 

 overlying beds. 



The evidence is conclusive where actual unconformity has been 

 shown, as well as where the beds are found resting on a lower mem- 

 ber (Pierre) of the Upper Cretaceous, and hence, in intermediate 

 areas where discordance has not been observed, it is reasonably cer- 



