1 882. i^9 Trans. N. Y. Ac. Set. 



high range of trachytic mountains, that sweep around to the northwest 

 and southeast, forming a crescent-shaped alcove in the western face of 

 the range, the points of which are about ten miles apart. Between the 

 horns of this crescent, and ihree or four miles southwest of the Ranch 

 Fort at Cove Creek, is a conical mountain of basalt, having the 

 ruins of a cinder cone at the summit ; for convenience we shall 

 call this old volcano the Cove Creek crater. From the perfec- 

 tion of its outlines, this crater seems to be of a very recent date, but 

 is clothed with a scattered growth of cedars. Judging from its gen- 

 eral appearance and the amount of weathering it has suffered, it is prob- 

 ably older than the post-Bonneville craters near Fillmore, Utah. The 

 Cove Creek crater is now in the condition of a nearly extinct fumerole, as 

 hot &ir and gases are said to escape from cracks and fissures near the 

 summit of the mountain. The area, between the base of the crater and 

 the mountains to the eastward of Cove Creek, is occupied by subaerial 

 gravels, except along the immediate base of the eastern range, where 

 volcanic tuffs appear at a number of localities. Along the line where 

 the alluvium slopes upward to meet the tuffs and volcanic rocks, is 

 where the majority of the sulphur mines have been opened. 



Prospecting for sulphur was begun at Cove Creek, about ten years 

 since, by Mr. C. A. Semler, and has been carried forward by him with 

 much energy ever since. At the present time fitteen mines have been 

 located, a few of which have been developed to a slight extent, and a 

 large number of prospects opened. The mines, however, have not yet 

 been worked sufficiently to make the sulphur from this locality an ar- 

 ticle of commerce. 



From the hasty examination that I was enabled to make, I find tha 

 the sulphur deposits at Cove Creek arrange themselves in three con- 

 venient groups, the divisions depending, however, more on the nature 

 of the cavities that have received the sulphur, than on any difference in 

 the manner in which it has been introduced. In one instance the sul- 

 phur occupies a nearly extinct solfatara ; again we find it impregnat- 

 ing and cementing beds of volcanic tuff; at other times, the sides of fist 

 sures are sheathed with a brilliant drusy lining of sulphur crystals. In 

 all of these instances it is evident that the sulphur has been derived 

 from deeply seated sources, having been expelled in a gaseous form 

 and condensed and crystallized in the cavities and fissures in the cooler 

 rocks above. 



In the mine named the Cleveland by Mr. Semler, situated about two 

 miles southward of the fort at Cove Creek, the sulphur occurs in quan- 

 tity, filling the crater of a solfatara. The bottom of the little valley, in 

 which the Cleveland is situated, is nearly circular, with a diameter of 

 about 1 200 feet, and is totally destitute of vegetation. Over the level 



