1882. i69 Trans. N. Y. Ac. Sct. 
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 three 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 air 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 Iccalities. 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 fifteen 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 
an: 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 1200 feet, and is totally destitute of vegetation. Over the level 
