136 J. B. Udtaher— Ceratops Beds of Wyoming. 



northerly direction, and skirting the western slope of the 

 Black Hills, it has been traced to the north line of Converse 

 county and on into Weston county. As stated above, the 

 eastern shore of the fresh-waters in which the Ceratops beds 

 were deposited was nearly that of the present border of these 

 beds. The eastern limit of the fresh-waters was confined to 

 the western slope of the Black Hills and that chain of minor 

 uplifts connecting them with the Laramie range to the south- 

 west. The Black Hills were at one time connected with the 

 Laramie range through the Rawhide range and a less elevated 

 series of uplifts extending in a northeasterly direction from 

 the latter to the southern limit of the Black Hills. Eemnants 

 of this connecting range are still to be seen in the bluff just 

 back of Lusk, known as Silver Cliff ; on Duck creek two and 

 one-half miles a little west of north of Lusk ; near the head of 

 Old Woman creek, about six miles north of the last mentioned 

 place ; in the ridge on the east side of Sage creek, two miles 

 below Hat Creek post-office and eight miles northeast of the 

 locality just mentioned ; in another bluff ten miles below this 

 and on the same side of the creek, but farther to the east ; and 

 doubtless in many other places as yet unobserved. The Cera- 

 tops beds were originally confined to the western slope of the 

 Black Hills and of the less elevated series connecting the 

 latter with the Rawhide range. This is conclusively shown 

 by the absence of the Ceratops beds not only on the eastern 

 slope of this range where they could have been removed by 

 erosion, but in the region to the eastward where all the beds 

 are approximately horizontal, and where, if they ever existed, 

 remnants of them, at least, should yet be seen. The surface 

 of the region to the east of the Black Hills and their south- 

 western extension, as just described, is composed for the most 

 part of Miocene deposits, with many sections showing the 

 underlying beds. In all such exposures in this region, hun- 

 dreds of which have been examined, the Miocene is underlaid 

 by marine Cretaceous or older formations. In no instance 

 have the Ceratops beds been observed east of the Black Hills 

 or their less elevated continuation to the southwest. 



The Ceratops beds proper, that is, those beds containing 

 remains of the Ceratopsidtv, are known to have a surface ex- 

 posure in that portion of Converse county embraced within 

 their eastern and southern border, as defined above, and a line 

 extending from that point on the latter where it passes under 

 the overlying beds a short distance west of Lance creek, 

 nearly due north to Weston county; i. e. the country drained 

 by lower Lance, Lightning, Cow, Doegie, and Buck creeks, 

 and that portion of the Chej^enne river and its tributaries 

 between the mouth of Lance creek and the north line of 



