Peterson : Miocene Beds of Nebraska and Wyoming. 23 



west, the western extremity lying within the State of Wyoming, in 

 Laramie County. The summit of Spoon Butte, which is represented 

 at the top of the section (Fig. i) is capped by a hard pinkish-gray 

 sandstone, thirty-five to fifty feet in thickness. In this hard cap of 

 sandstone, which is regarded as the top of the Upper Harrison beds, 

 our party found no fossils. The base of this elevation is composed of 

 the Lower Harrison beds. 



UpperHam'son Beda 



IT 200 ft 



Lower HorrisonBeds 



200 ft 



H Monroe Creek Beds 



300 ft 



Gering Beds 



™. 200 & j 

 Oltp'ooene Beds 



& 150 ft 



Fig. I. A section of the Lower Miocene of western Nebraska and eastern 

 Wyoming. 



The Gering Beds. 



The Gering horizon forms the contact between the Oligocene and 

 the lower Miocene formations over extensive areas in eastern Wyoming 

 and western Nebraska, and perhaps also parts of eastern Colorado. At 

 Squaw Butte, the northern limit of the lower Miocene, where the sec- 

 tion represented in Fig. i was obtained, the Gering sandstones rest 

 directly on the Leptauchenia clays, which compose the uppermost 

 Horizon of the Oligocene formation. No fossils were found in this 

 horizon in the neighborhood of Squaw Butte, but farther east, near 

 Sand Creek and near Chadron, Nebraska, a few remains were found. 



? Mesoreodon. 

 Leptauchenia} 



List of the Fauna. 



The Monroe Creek Beds. 



In the vicinity of Squaw Butte it is quite difficult to separate this 

 horizon from the underlying Gering beds by lithological characters 

 alone. While remains of Leptauchenia were found in the lower part 



*The material referred to Lepiauchenia differs but slightly from that referred to 

 L. decora Leidy, from the Oligocene, and should not in my judgment be regarded as 

 belonging to the genus Cyclopidius. 



