1922] Whitman: Genesis of the Ores of the Cobalt District 283 



distribution is, however, due to the variation in size or in prevalence, or both, 



of the voids in the rocks Nevertheless all sedimentary rocks below the 



water-level are saturated to an unknown but great depth. But saturation does 

 not imply an abundant flow to a conduit or fissure But making all allow- 

 ance for this diminution of storage capacity there is a vast quantity of water 

 contained in the sedimentary rocks in their unaltered state at all depths; and at 

 high temperatures, which are an essential condition of our problem, the rate of 

 flow and therefore the rate of escape to fissures, etc., is undoubtedly accelerated. 

 Moreover, brittle rocks such as quartzite, sandstone, and limestone, which have 

 been folded and otherwise disturbed, are usually traversed by fractures, faults, 

 and joints, and these, together with the partings of stratification, afford compara- 

 tively free access of surface waters to the limit of the zone of fracture of such 

 rocks. 



He also points out that botli walls and periphery of an igneous 

 mass will probably be fractured as a result of cooling phenomena, 

 and that the ground water will move laterally through fractures and 

 through them ascend both beside and through the igneous mass. 

 Farther on he says : 



The failure of ' ' evidence of fracture or paths which could have been followed 

 by the water ' ' applies equally well to magmatie as to meteoric waters, and is 

 of little moment when we reflect that the water in either event was probably in 

 the form of superheated steam. 



In the concluding paragraph of this same paper Lawson says : 



Now if the view which Spurr expresses is correct, and it is substantiated by 

 a great many observations, the hypothesis of magmatie waters becomes far-fetched 

 and difficult of acceptance. It throws us back for the source of the solutions 

 upon a residual differentiate far in the depths, as Spurr holds. It fails to 

 account for the restraint of the magmatie waters till this residual stage is arrived 

 at. It assumes great depths for small intrusions which were probably injected 

 from narrow vents. And it fails to explain the peripheral disposition of the 

 ores deposited from the waters thus rising from a presumably central reservoir. 



Waldemar Lindgren in his "Mineral Deposits" 12 indicates his 



belief that the flow of water through rock pores is exceedingly meager 



and practically nil at really moderate depths. 



Kemp ami Fuller have both brought out the fact that the deep sedimentary 

 beds are often remarkably dry. The well 4262 feet deep at Wheeling, West 

 Virginia, was in absolutely dry rocks for the lower 1500 feet. Wells sunk at 

 Northampton, Massachusetts, and at New Haven, Connecticut, to depths of 4000 

 feet have failed to obtain water. A number of other instances are mentioned, 

 and in many cases the dry part consists of sandstones or other porous rocks. 



Again he says : 



Van Hise suggests that the decreasing density and viscosity of water at higher 

 temperatures may lessen the head necessary for ascending springs, but it may be 

 doubted whether these factors would ever offset the great friction encountered 

 during the downward passage. 



12 Edition 1919, p. 29. 



