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University of California Publications in Geology [Vol.8 



tained. If the suppositious magmatic waters can rise at C there is 

 no reason why the real meteoric waters should not do so also. It seems 

 to me, therefore, that it devolves upon the supporters of Professor 

 Lindgren's view to explain the impossibility of such a circulation 

 upward along the contact at temperatures of from 300° to 1000° C. 

 The Daubree experiment has nothing to do with the case. 



But the zone of rupture due to shrinkage is not confined to the region 

 exterior to the intrusion. The latter is itself affected by the process as 

 well as by the faults due to less local stresses as at D. The igneous rock 

 becomes sheared and dislocated, so that the meteoric waters in the 

 underlying strata have access to its interior, rising at high pressure 

 and at high temperature through its lower part where the magmatic 

 sulfids abound. The igneous rock may thus be leached of a portion 

 of its metallic contents and supply the minerals for deposition in the 

 fissure-replacement or contact-replacement veins above, either in the 

 igneous mass or in the encasing rocks. 



Lateral Movement of I he Circulation. — In an effort "to make the 

 real position of the leaching theory a little clearer" Lindgren states 

 his second objection as follows : ' ' The metals, etc., were extracted from 

 the intrusive rock, that is, from a hot body having a temperature of 

 from 500° to 1500°, and deposited in the adjacent, cooler sediments, 

 say at temperatures from 300° to 1000° C. Consequently the circu- 

 lation of the atmospheric waters would really take place in a lateral 

 direction and not simply along the contact as maintained by Lawson." 

 I am somewhat at a loss to answer this objection. It seems so trivial 

 that I fear my critic has not fully expressed himself. I have stated 

 that "the circulation would always be upward on the periphery of the 

 hot mass." But this surely does not preclude a horizontal component 

 of motion in the zone of upward circulation. The term "circulation" 

 implies that, I see no difficulty in the conception of the rising meteoric 

 waters permeating the hot igneous mass, both from its limiting surface 

 and by way of fissures traversing it, and carrying silica, iron, salts of 

 the ore metals, etc., to (1) positions in the upper cooler parts of the 

 mass, as may very possibly have been the ease at Butte, 1 " (2) higher 

 positions on its contact with the adjoining rocks in the fashion 

 advocated by Becker 16 for the Comstock, or (3) higher positions within 

 the encasing rocks, as may well have been the case at Bisbee or 

 Bingham. That the waters in their upward circulation should also 



is Cf. Univ. Calif. Publ. Bull. Dept. Geol., vol. 8, no. 1, 1914. 

 is IT. S. G. S. Monograph III. 



