OF COMMON SALT, 



149 



masses its tendency is to contraction, to perfection of crystal- 

 line structure ; given a sufficient lapse of time, and suitable 

 conditions, and it will effect its purpose. What period of 

 time has this force had at its disposal in the most recent of 

 our mines of rock salt ? As before stated, many thousands, 

 nay, many tens of thousands of years. During all this time, 

 moreover, what pressure has been at work on the salt mass 

 crushing it down, with the irresistible force of the most 

 powerful hydraulic ram, into a solid homogeneous mass! 

 The pressure, like the time, is beyond our computation ; we 

 can only measure it by its effects. We see the rock salt 

 sometimes interleaved with sedimentary masses, which have 

 been crushed into compact rocks. We find it covered over 

 with hard coal, which we know to have been, once, a loose 

 vegetable deposit. We find a variety of other rocks, over- 

 lying the salt, bearing the same testimony with more or less 

 force ; and in some cases, as in the Austrian Alps, we find the 

 salt buried, at the present time, under masses of rock, whose 

 weight and pressure we can calculate. What wonder, there- 

 fore, that rock salt is a crystalline mass, and not as the salt 

 deposits recently formed in our shallow bays. If the case 

 were otherwise, there would be good ground for rejecting the 

 marine hypothesis. Let it be remembered that the protozoa, 

 whose fossil remains make up the chalk cliffs of England, 

 were swarming in life, in our northern seas, long after the 

 deposition of all but the most recent beds of rock salt. 



Another peculiarity of rock salt, which is held by some to 

 tell against the marine view of its origin, is the rare presence 

 of fossil shells and fishes, &c, in its formations. It is argued 

 that if this salt was deposited by the evaporation of an inland 

 sea, we should find abundant organic remains in it, . as we 

 know that salt acts antiseptically, that is, it preserves organic 

 remains. This comparative absence of fossils can, however, 

 be explained on natural grounds, Life ceases to be 



