FOiniER GLACIATION OF MIDDLE AND NORTH PARKS. 67 



party, and his notes make frequent reference to glacial phenomena observed 

 along the route. At the base of Gray's Peak distinctly preserved moraines 

 were observed, but no striations or polished surfaces. Farther down the in- 

 dication of the former passage of a glacier through the caiion were abundant. 

 Between Brown's Mills and Georgetown the rocks in the bottom of the valley 

 are finely polished, and the projecting ledges rounded and smoothed ; there 

 were also occasional evidences of moraines, although not especially marked 

 in character. The following passage is quoted from Professor Brewer's notes : 

 " Some few glacial traces were observed for the first few miles below George- 

 town [elevation, 8,412 feet], but we saw none whatever below Idaho [7,535 

 feet]. For most of the distance [from Idaho to the Plains] it was impossible 

 that an}- considerable glacier should ever have passed down that portion of 

 the valley since it had its present features. Frequent jagged outliers at 

 short turns in the valley showed that no glaciers could ever have passed 

 them and left them in their present shape ; in fact, but meagre traces were 

 found below Georgetown, and these only for the first five or six miles." 



Farther north, about latitude 40° 15', in the Middle Park region, Mr. A. R. 

 Marvine has indicated the existence of large moraines and other proofs of 

 former glaciers. The locality is near Grand Lake, in the valley of the North 

 Fork of Grand River, between the southern end of the Medicine Bow Range 

 on the west and the Long's Peak Group on the east. The elevation of the 

 lake is 8,153 feet, and the moraines do not appear to have descended much, 

 if any, below this level. There are also proofs of the former existence of a 

 glacier of moderate size, which came down the valley of the East Fork of 

 the same river, which takes its rise between Mount Audul^on (13,173 feet) 

 and Arapahoe Peak (13,520 feet). 



The phenomena of glaciation in the ranges which enclose the North Park 

 and extend beyond it to the north as far as the parallel of 42' have been 

 briefly indicated by Mr. A. Hague.* The Medicine Bow Mountains extend 

 from latitude 40^ 15' to 4r 40', having an approximate northwest trend. 

 The western side of this range shuts in the North Park on the east and 

 nortli, and still farther northward forms the boundary of the North Platte 

 Valley, which lies between it and tlie Park Range. As thus defined, the 

 Medicine Bow Range is about a hundred miles in length. Its highest sum- 

 mits a little exceed 13,000 feet in elevation. All the more elevated regions 



* See Eeport of Fortieth Parallel Survey, Vol. II. p. 96, for the Medicine Bow Eauge, and p. 131 for the Park 

 RauKC. 



