ADAMS HILL. 167 



the flat to the north, which is designated on the map as Mineral Point. The 

 ores do not occur in compact form as the filling of chambers, but are found 

 in bunches in cracks and seams in the limestone, and although masses of 

 ore of considerable size are not unknown, they exist in the form of silicified 

 limestone more or less impregnated with silver and lead minerals. 



The ores. — The Eureka quartzite, which Mr. Hague has placed just above 

 the Pogonip limestone, at one time covered the whole of Adams Hill, and 

 there is still a small area of this rock to be seen on the northwestern slope 

 of the hill near the road to the Wide West mine. It is not impossible that 

 the quartz in the ore was derived from this quartzite. Still it is not likely, 

 however, as it would be necessary for the silicious solutions, which were 

 formed from this quartzite, to traverse the underlying Hamburg shale 

 as well as the Pogonip limestone. Also, if the quartz in the ore was 

 derived from the quartzite, it is likely that the ore was as well, as the two 

 seem to have been deposited simultaneously, though this might possibly 

 have occurred where the components of the ore were derived from different 

 sources. The Eureka quartzite also carries small amounts of the precious 

 metals; but the same objection to the secretion of the ore from this rock 

 can be advanced that was offered in regard to the secretion of the ore in 

 Ruby Hill from the outside country rock. It could hardly have passed 

 through the Hamburg shale. It is possible, however, that the ore in the 

 Pogonip limestone was derived from this source, though, as has been 

 explained in Chapter VII., it is more justly referable to another source. 



Another noteworthy fact in regard to the ores of Adams Hill is that 

 they carry as a rule a high percentage of gold, although there are some 

 that carry no gold whatever. The contents in gold is a distinctive feature 

 of this region. Lead in the form of carbonate and sulphide is common, and 

 both the Bullwhacker and Williamsburg mines have produced large quan- 

 tities of this metal. 



Quartz-porphyry as a source of the ore. — The quartz-porphyry which occurs in the 

 Bullwhacker mine has already been mentioned (Chapter VII.) as the prob- 

 able source of the ore in its immediate neighborhood. This porphyry still 

 contains considerable quantities, relatively speaking, of gold, silver, and 

 lead (see Chapter XI.), and although it does not cover a very extensive 



