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THE ULTIMATE SOURCE 



ranging from 100 to 275 feet. In England a large bed of 

 rock salt lies beneath the valley of Cheshire, from Malpas to 

 Congleton. There are about 25 pits now open in this region, 

 of which seven are at Marston, and six at Winsford. About 

 40 old workings are closed. The Northwich mine has been at 

 work for 210 years. The two beds of rock salt in the Marston 

 mine are, each, about 90 feet in thickness. The annual 

 output of rock salt and salt made from rock salt brine, in 

 England alone, is estimated at about two million tons at the 

 present time. This is but a rough sketch of the mass of 

 rock salt in three or four of our best known salt regions ; 

 taken in connection with the geographical distribution of 

 rock salt, it enables us to form some idea of the enormous 

 masses of rock salt which exist scattered over the globe, 

 known, and unknown. 



It would not be rash to estimate the known salt deposits 

 at one-half of the existing whole, since much more than half 

 the globe is covered with water and out of ken, and the 

 mineral resources of the habitable portion are as yet imper- 

 fectly explored. This salt, if the views herein expressed 

 regarding its formation be correct, was separated from the 

 sea by evaporation. In this process, oceans of salt water 

 have been evaporated, and oceans of aqueous vapour 

 have been carried back, in clouds, from the rock salt forma- 

 tions to the sea. We have no reason to suppose that the 

 sea is either greater, or less, in volume, now, than it was 

 in the Pre-Silurian period. On the contrary, geologists 

 conclude that it remains the same. Hence we have herein, 

 if the aqueous theory be correct, excellent reasons for suppos- 

 ing that the primeval sea was much more saline than our 

 own. Dr. Warth has calculated the cubical salt contents 

 of the Mayo mines at 10 cubic miles. From the very early 

 period at which the Mayo mines were formed, down to the 

 Tertiary, we have the geological record as a witness, that 



