B. S. Lull — Mammals and Homed Dinosaurs. 335 



sandstone and is from 1 to 3 feet thick. The bones and teeth are 

 mingled with sand, nodules of clay and several varieties of fossil 

 nuts." 



2. Hatcher's section, 1893.— Hatcher (1893, p. 137) thus 

 describes the area : 



"The Ceratops beds are made up of alternating sandstones, 

 shales, and lignites, with occasional local deposits of limestones 

 and marls. The different strata of the series are not always con- 

 tinuous, a stratum of sandstone giving place to one of shales and 

 vice versa. This is especially true of the upper two-thirds of the 

 beds. The lack of continuity in the different strata has rendered 

 it well nigh impossible to establish any definite horizons in the 

 upper members of the series. All the deposits of the Ceratops 

 beds of this region bear evidence of having been laid down in 

 fresh waters. . . There is no evidence that marine or brackish- 

 waters have ever had access to this region since the recession of 

 the former at the close of the Fox Hills period. 



"The sandstones largely predominate in the lower members of 

 the beds. They are always fine-grained, massive to well-strati- 

 fied, and nearly white to yellowish brown in color. They are 

 occasionally compact and hard, but for the most part quite soft 

 and friable. They are composed of sharp, angular grains of 

 quartz with some clay and mica, the whole being loosely cemented 

 together with carbonate of lime. Almost everywhere in the 

 sandstones are numerous concretions of varying size and shape. 

 Some are almost perfect spheres and vary from the size of a 

 marble to 18 to 20 feet in diameter. Others are from a few inches 

 to several feet in transverse diameter and sometimes several hun- 

 dred feet in length, a cross section forming a nearly perfect 

 circle. Others still are very irregular in form. These concre- 

 tions usually show no concentric structure, and while they some- 

 times enclose foreign objects, as a Triceratops skull or a single 

 bone as a nucleus, they are for the most part simply centers of 

 solidification and not true concretions. This is frequently shown 

 by the cross-bedding in them, so often seen in the sandstones 

 themselves. 



"The shales are almost entirely wanting in the lower 400 feet 

 of the Ceratops beds, but they are well represented in the suc- 

 ceeding series. They are quite soft and loosely compacted, com- 

 posed mostly of clay with more or less sand in places. The pre- 

 vailing color is dark brown, but they are sometimes red or bluish. 

 They are well stratified and finely laminated, and contain occa- 

 sional limestone concretions enclosing numerous invertebrates. 



" The lignites occur in thin seams, never more than a few 

 inches thick, of only limited extent, and with many impurities. 

 At no place in the Ceratops beds of this region have workable 

 coal beds been found. These do occur, however, in the Ceratops 

 beds of Montana .... 



" Intercalated with the sandstones, shales, and lignites, are 

 quite local deposits of limestones, clays, and marls. The latter 



Am. Jour. Sci. — Fourth Series, Vol. XL, No. 238. — October, 1915. 

 22 



