Park. — Origin of Metal-bearing Solutions. 103 



tioii with respect to the action of meteoric waters, and admits 

 that the role of igneous intrusions may be very considerable.* 



It has been suggested by the opponents of lateral secretion 

 that the metals contained in the silicate minerals of eruptive 

 rocks are not primary but secondary constituents. According 

 to their view, lateral secretion is only a process of concentration. 



Ascension of Solutions. 



According to this theory it is assumed that the material 

 which fills a lode has been brought in solution from great depths, 

 and not derived from the rocks in the immediate vicinity of the 

 lode. 



In his classic memoir on " The Genesis of Ore-deposits," 

 the late Professor Posepny, an ardent supporter of the ascension 

 h)-pothesis, laid great stress upon the occurrence of sulphur 

 and cinnabar at Sulphur Bank, California, impregnating a 

 decomposed basalt, and still mildly in process of formation 

 from gaseous emanations and hot mineral waters. 



Similar conditions exist at Steamboat Springs, in Western 

 Nevada, where we have an example of a mineral vein in process 

 of formation. The matrix is banded siliceous veinstone, con- 

 taining iron and copper sulphides, sulphur, and metallic gold. 



Sandberger, who was an ecjually strenuous supporter of 

 lateral secretion, objected to this view on the ground that he 

 knew of no spring which deposited mineral incrustations on the 

 walls of their channels. He regarded the Sulphur Bank and 

 Steamboat Springs phenomena as exceptional. 



Becker, who made a special examination of the deposits at 

 Sulphur Bank and Steamboat Springs, strongly opposed the 

 views of the extreme ascensionists. And with regard to the origin 

 of the deposits he expressed the following views : " The evi- 

 dence is overwhelming that the cinnabar, pyrite, and gold of 

 the quicksilver-mines of the Pacific Slope reached their present 

 positions in hot solutions of double sulphides which were leached 

 out from masses underlying the granite, and the granite itself."! 

 Further on he says, " I regard many of the gold-veins of Cali- 

 fornia as having an origin entirely similar to that of the quick- 

 silver-deposits." 



Becker's views postulate a new hypothesis lying midway 

 between the ascension and lateral-secretion theories, and now 



* C. R. van Hise, "' The Genesis of Ore-depo.sits," New York, 1901 : 

 Discussion, p. 763. 



t G. F. Becker, " Tlie Geology of tlie Quicksilver-deiiosits of the 

 Paoifio Slope," U.S. Geol. Survey, Vol. xiii, 1888, p. 449. 



