229 



from a mass of rock which fell from one of the highest 

 mountains .... The largest mass yet reported from 

 California weighed 1341bs 7ozs. A remarkably beautiful 

 mass, consisting of a congeries of crystals weighing 101 

 ounces (value $4,000), was found in 1865, seven miles from 

 George Town, in El Dorado County. At Maisk, in the Ural 

 Mountains, a nugget of gold was found — weight, 961bs. It 

 would seem, therefore, that the largest masses of gold known 

 were found in Australia. 



Theories Regarding the Origin of Gold Veins and theie 

 Mode oe Occurrence. 



Regarding the origin of gold found in quartz veins, there 

 is much that is obscure or little understood. Of course 

 nearly all authorities now agree in referring the formation of 

 auriferous quartz veins to an aqueous origin. But suppose 

 we admit that the gold is carried into rock fissures in solution 

 with quartz from certain strata in the surrounding rocks, we 

 have still to enquire how and from whence came the gold 

 there in a finely-divided state ? What is the true cause of 

 shoots of gold ? Why, for example, are auriferous quartz 

 veins principally confined to rocks of Palasozoic age ? Why 

 should particular rocks, say diorite, appreciably affect the 

 deposition of gold in veins passing through that rock ? What 

 is the exact thermal condition and the exact nature of the 

 fluid which will hold silica, gold, and other metals in solution 

 at the same time and in such a manner that they may in some 

 form be deposited together? Many speculations have been 

 advanced by able authorities, which, though of great value, 

 fail to satisfy all the conditions required to arrive at a proper 

 appreciation of the subject. 



According to J. Arthur Phillips," the formation of auri- 

 ferous veins is now going on in various parts of the Pacific 

 Coast. He states (see p. 601, LyelPs Elements of Geology) — 

 " For example, there are fissures at the foot of the eastern 

 declivity of the Sierra Nevada, in the State of that name, from 

 which boiling water and steam escape, forming siliceous in- 

 crustations on the sides of the fissures. In one case, where 

 the fissure is filled up with silica, enclosing iron and copper 

 pyrites, gold has also been found in the veinstone.'' And 

 again, with reference to California, he states: — "The auriferous 

 quartz of these drifts is derived from veins apparently due 

 to hydrothermal agency." Again, Sonsdadt states that "the 

 sea water of the British coasts contains in solution, besides 

 silver, an appreciable amount of gold, estimated by him at 

 about one grain to a ton of water."-' 1 



a Phillips on "The Goldfields of California."— Proc. Roy. Soc. Lond.,1868. 

 a J. Sterry Hunt. 



