265] F. Reeves 67 



is a generally accepted fact 2 and since there is an equilibrium 

 between the amount of the C0 2 in the air and in the sea 

 water it is to be expected that the sea water at times, when 

 there is the greatest amount of C0 2 in the atmosphere, will 

 hold a comparatively larger amount of calcium in solution 

 as the solubility of calcium carbonate is a direct function of 

 the amount of C0 2 present. 3 



The increase in concentration with depth is also an argu- 

 ment that the brines are indigenous to the rocks in which 

 they occur. Kichardson, 4 however, suggests that this is due to 

 the fact that there has been an upward diffusion of salts from 

 the rock salt deposits that are known to underly the strata 

 in question. But it has been pointed out that there are dry 

 sands in the area under consideration intervening between 

 these lower water-bearing horizons and the Mississippian 

 sands and, as diffusion through dry strata is impossible, this 

 suggestion seems untenable. Again, on this assumption it is 

 difficult to understand why sodium would increase in relative 

 amount with increase in distance from the salt beds. Refer- 

 ence to the analysis given will show that the Pennsylvanian 

 brines are richer in this salt than the Lower Devonian. It 

 appears more likely that the concentration is due to a capil- 

 lary migration of the water away from the sands in which it 

 occurs and in which it accumulated. This migration would 

 remove part of the water and most likely leave the salt behind, 

 because fine-grained sediments have an absorptive effect on 

 solutions passing through them 5 which would result in a 



2 Chamberlain, T. C. " The influence of great epochs of limestone 

 formation on the constitution of the atmosphere." Jour. Geol., vol. 

 vi, 1898, pp. 609-621. 



3 Johnson, John and Williamson, E. D. "The rOle of inorganic 

 agencies in the deposition of calcium carbonate." Jour. Geol., vol. 

 xxix, No. 8, 1916, pp. 729-750. 



4 Richardson, G. B. " Note on the diffusion of sodium chloride in 

 Appalachian oil field waters." Jour. Wash. Acad. Sci., vol. vii, no. 3, 

 1917, pp. 73-75. 



6 Turrentine, J. W. " The occurrence of potassium salts in the 

 saline of the United States." Bureau of Soils, Bull. 94, 1913. 



