FORT UNION OF CRAZY MOUNTAIN FIELD, MONT. 19 

 Base of Fort Union No. 1 



Bear < 



Hell 



Creek 



Feet 



'Clays with thin and inconstant sandstones, a more prominent 



sandstone at the top not well exposed here 280 



Gray to buff platy sandstones in beds usually one to three feet 

 thick, with thicker shale partings 330 



610 



Pale variegated shale with occasional soft blocky sandstones. 765 



Pale gray sandstone 10 



Mainly pale variegated sandstone 270 



Heavy gray sandstone, with some shale 145 



Pale white to greenish clays with brown concretionary layers, 



sandstones increasingly prominent toward the top 660 



1,850 

 Base of Hell Creek 



Yellow Sandstone and Somber Clay (Not measured) 



Dinosaurs are found in the Hell Creek in this region also, but no 

 animal fossils were found in the Bear. 



The discrepancy in thickness of the Bear between this section and 

 that previously given, about 110 feet, seems too great to be due 

 entirely to difficulty of accurate measurement and is probably at 

 least in part a real difference. The localities are about 8 miles apart 

 in a straight line. It is also possible that the limits taken do not 

 exactly correspond in the two sections, as all the formations concerned 

 are highly variable. 



Knowlton (in Stone and Calvert, 1910, p. 749) reports the following 

 leaves from "200 feet below the top of the Lance Formation", that is, 

 in the Bear at this locality: Sapindus affi,nis, Sapindus grandifoUolus, 

 Plat anus aceroides, Platanus sp.?; and the following from a level still 

 lower by 200 feet, probably still in the Bear: Sapindus 7 grandifoUolus, 

 Sapindus sp., Platanus raynoldsii. Knowlton unreservedly called 

 these Fort Union, but this has no bearing on the question here con- 

 sidered, since he also called true Hell Creek and Lance floras Fort 

 Union. All these species are reported from beds probably of Lance 

 age, but they are all equally characteristic, or considerably more 

 abundant, in the true Fort Union. 



Throughout the northern part of the field at least, and generally 

 except where all the subdivisions of this part of the section tend to 

 merge indistinguishably into the Livingston, the beds between the 

 Hell Creek and the Fort Union No. 1, or basal Lebo, are a good 

 lithologic unit. The scanty data also suggest a distinctive paleon- 

 tological character. These facts and the possibility, or as I believe 

 probability, that the beds should be classified as Paleocene, or asso- 

 ciated with the Fort Union, rather than as Cretaceous and associated 

 with the Hell Creek or "Lance" make it highly advisable to distinguish 



