, 
48 The American Geologist. January, 1892 
contact with the dykes. There is also more or less mineralization 
in places, either in the form of vein-like beds, or in isolated 
patches and bunches at a considerable distance from any erystal- 
line rock—hbut not outside of the crystalline and whitened por- 
ly 
tions of the limestone. his last observation applies particularly 
to some of the copper ores found in the midst of the limestone 
existing primarily as the variegated sulphuret—erubescite. These. 
ore nodules have decomposed and have formed green carbonate of 
copper, which stains the rock for a considerable distance around 
and beyond the original nodule, or bunch, of sulphide. In such 
places free gold of high grade may be found by crushing and 
washing the rock. This noble metal occurs also independently 
of any cupriferous mineralization in the midst of masses of 
colorless tremolite, in coarse grains and strings in very much the- 
same form in which it is found in other regions ramifying through 
quartz. This is an unusual and unique association of gold. 
It has been found, but rarely, in close association with greenish 
black hornblende in veins composed partly of quartz and partly 
of dolomite, but never before, to my knowledge, in white tremo- 
lite. This tremolite carries, also, some small disseminated erys- 
tals of iron pyrites. 
The limestone in which the gold occurs appears to be the Lower 
Carboniferous, or Mountain limestone, as shown by an abundance 
of fossils, chiefly of the genus Productus, founda short distance 
vast of Gold Hill. 
From the fact that coarse gold in placer deposits has been 
found at Osceola and its vicinity, nearly south of the [bapah 
mountain, it would appear that there is a gold region extending 
north and south near the Nevada and Utah line, and that the 
placers were formed during the period of great precipitatiom or 
rainfall which preceded the present era of gradual dessication 
At the place where gold is now taken from heavy deposits of 
boulders and gravel, the flow of water is wholly inadequate to the 
formation of such deposits. Probably the deposits were formed 
during the great glacial epoch of which there are such magnificent 
records in the Sierra Nevada, and the Wahsatch as well as in the 
ancient beaches of lake Bonneville. A good supply of water, 
even for ordinary purposes, is now one of the greatest needs of 
the Deep Creek region. 
