IOWA ACADEMY OF SCIENCES. 95 



pretty mountain stream, which has its sources in the great 

 range just north of this valley, and joins the Bear a mile east 

 of the Springs. Some four miles up, this creek has made for 

 itself a wild, deep gorge or canon, and here, in 200 or 300 

 yards, it falls perhaps 200 feet. In this cailon great masses of 

 rock lie in every position and these show plainly a bedding, 

 although the main walls of this canon are almost vertical 

 sheets of metamorphic rocks. 



At a point some six or seven miles northwest of Steamboat 

 Springs, at some springs we visited, the temperature of the 

 water is said to be about 160 degrees F. The rocks are, in 

 part, at least, very dark colored, compact and fine grained, 

 resembling diorite. Enough has been said to show that the 

 Park range, immediately north of Steamboat Springs, is 

 largely metamorphic, abounding in granites, syenites and vol- 

 canic rocks. In this vicinity the valley of the Bear is from 

 one-half mile to a mile in width. Directly opposite the 

 village, which is almost wholly on one street on the north side 

 of the river, is a rather lofty and rugged mountain, but for the 

 most part the country on the south side of the Bear is much 

 less precipitous and is not covered by timber like the moun- 

 tains close on the north. The valley here has undoubtedly 

 been the seat of an immense glacier, which was well supported 

 from the north by great numbers of glaciers lying on the 

 southern face of Park range. 



One very conspicuous moraine lies in the village, and to 

 improve the single straight street this moraine has been cut 

 transversely. In the village there are four charming little 

 creeks, all coming from the mountains on the north. Not a 

 single creek enters the Bear river, for several miles, from the 

 south. Opposite the eastern or upper end of the village, 

 some 300 feet above the valley of the river, is an "onyx 

 mine." Here a horizontal tunnel has been carried i^erhaps 

 200 feet into the side of the mountain. A cross section of this 

 tunnel is not less than six feet square. It is perfectly dry and 

 is wholly in what seems to be unmodified drift. The onyx is 

 scattered through this drift in pieces varying from a cubic 

 inch to blocks three or four feet square and eight or ten feet 

 long. These pieces show, in many cases, unmistakable evi- 

 dence of erosion or weathering, and they are so packed in with 

 the clay and granite pebbles that we could hardly pull out 

 small pieces from the walls of the tunnel. How extensive the 



