246 STANTON 



formation and there are indications that the hne of lithologic change 

 is not a constant horizon throughout; thus it may be that some of the 

 lower members represented as Laramie formation in this region be- 

 long to the Fox Hills in other districts. 



According to Darton the "Laramie formation" (i.e., "Ceratops 

 beds") of the Newcastle quadrangle 



consists of soft, massive sandstones intercalated with carbonaceous 

 sandy clays. The thickness is 700 to 800 feet, as nearly as can be 



ascertained Next above the Fox Hills beds are 80 



feet of gray clays overlain by sandstones. The sandstones 

 consist mainly of fine-grained, loosely cemented sand of light-buff 

 color, often having a thickness of 40 feet. They contain very charac- 

 teristic concretions of gray color and great variety of shape. 



The beds of shale which occur interbedded among the sandstones 

 of the Laramie formation are usually of dark gray color and in places 

 lignitic, but no coal deposits have been found in them in this region. 



If Barton's observations are correct the rapid northward thinning 

 of the sandstones beneath the "Ceratops beds" isduenot to erosion 

 of the upper members but to lateral replacement of the lower members 

 by shale. 



Northward from Weston County, Wyoming, to Hell Creek on the 

 Missouri River in eastern Montana the presence of the " Ceratops 

 beds" is indicated by the occurrence of the characteristic dinosaurs 

 at many localities, though it may not be possible to trace the formation 

 continuously all the way. At these localities the sandstones repre- 

 senting the Fox Hills are either thin or entirely lacking, the " Ceratops 

 beds" often resting, as at Forsyth and Myers, Montana, directly on 

 a shale that is usually called Pierre, though Meek and Hayden early 

 recognized the fact that its fauna contains a mixture of Pierre and 

 Fox Hills species. 



Hell Creek, Montana. — This locality, just south of the Missouri 

 River in eastern Montana, has been made prominent by the collections 

 and descriptions of Mr. Barnum Brown''^ of the American Museum 

 of Natural History. The base of the section is "Pierre shale," with 

 a total exposed thickness of nearly 200 feet, which has yielded a 



"The Hell Creek beds of the Upper Cretaceous of Montana. Bull. Am. 

 Mus. Nat. Hist., Vol. XXIII, 1907, pp. 823-845. 



