1897.] Geology and Paleontology. 529 
underlying Laramie. Cross,’ Hills’ and others have observed that beds 
lithologically resembling the Denver bed and ina similar stratigraphic 
position above the Laramie, occur at several widely separated localities 
in western and southwestern Colorado. In southern Montana Weed* 
has defined the Livingston formation as a very thick series of strata 
lithologically comparable with the Denver beds, resting unconformably 
on the Laramie and yielding a small flora more closely related to the 
Denver flora than to any other. The same geologist’ also finds beds 
that he refers to the Fort Union, overlying the Livingstone. All these 
formations are older than the Wasatch, and we should naturally ex- 
pect to find them in eastern and southern Wyoming, or, if they are 
absent there, their places should be indicated by unconformities. 
“ The Denver and Arapahoe beds have yielded representatives of a 
remarkable reptilian fauna consisting largely of horned dinosaurs of 
the family Ceratopside. The presence of this family in the Ceratops 
beds of Converse County and probably at Black Buttes has suggested 
the very reasonable query whether the beds containing them at these 
places also are not younger than the true Laramie. The facts we have 
presented relative to the stratigraphy and paleontology of the Black 
Buttes dinosaur horizon seem to us convincing that it is in the Laramie 
and near the base of that formation. It is less than 200 feet above the 
marine Cretaceous, and there is no evidence of a break® nor any abrupt 
lithological change. The character of the flora and of the invertebrate 
fauna also, so far as the species have a distribution in recognized hori- 
zons elsewhere, favors its reference to the Laramie. If the Dinosaur 
bed of Black Buttes is not Laramie, then the Laramie is either absent 
or is represented only by about 100 feet of sandstone. The overlying 
beds up to and including strata with a Fort Union flora seem to form 
a continuous series that is indivisible either structurally or lithologi- 
cally, and we can see no reason for placing the top of the Laramie 
lower than the base of the lowest bed with a Fort Union flora. 
“ Closely similar conditions are seen in Converse County, the princi- 
pal difference being a greater development of the beds. The sand- 
stones at the base overlying the Fox Hills are a few hundred feet 
? Amer. Kaas Sci., Vol. XLIV, 1892, pp. 19-42. 
8 Proceeds, Colo. Sci. Soc., Vol. III, pt. III, 1890, pp. 390-397. 
* Bull. U. S. Geol. Surv., No. 105, po 
5 Amer. Geol., Vol. XVIII, p pp- 201-211, 1 
ê The mappini unconformity between nai Point of Rocks and Bitter Creek 
groups has no bearing on this question, since it is below marine beds belonging to 
the Fox Hills, 
