SALT AND THE AGE OF THE EARTH. 



By G. W. BULMAN, M.A., B.Sc. 



In the able hands of Prof. Joly the salt of the ocean has been 

 made to give an answer to the question of the age of the earth. 

 The general idea of it is perfectly simple, though the difficulties 

 of working it out in detail are immense. Salt is being carried 

 down year by year into the sea where it accumulates. If then 

 — assuming an original saltless ocean — we divide the amount of 

 salt in the ocean by the amount carried in every year, the 

 quotient will be the age of the earth. Prof. Joly works it out 

 to 99 million years, which he afterwards, making allowances 

 for possible sources of error, reduces to 90 millions. 



Two special comments suggest themselves. 



One is on a matter of fact regarding the actual occurrence 

 of salt in the geological sequence of strata. The other touches 

 on the underlying and necessary assumption that the primeval 

 ocean was practically saltless. 



Salt occurs in the strata of various geological ages. In 

 our own country great deposits occur in the Trias . In Germany 

 immense quantities — including the famous potassium and 

 magnesium salts of Stassfurt — are found in the Permian. 

 The noted salt mines of Wieliczka are of Miocene age. In India 

 in the Salt Range, " It occurs in solid cliffs, which for extent 

 and purity are stated to have no rival elsewhere in the world." 

 The Indian salt is of Devonian age. In the Silurian of North 

 America, again, deposits of salt 14 to 40 feet thick occur. 



Now if we compare in a broad and general way these salt 

 deposits from the Silurian to the Miocene it is impossible to 

 suggest that the Tertiary oceans were salter than the Primary, 

 as they ought to have been. The seas which could give us the 

 salt beds of the Salina group of North America, and those of 

 the Indian Salt Range must have contained — one suggests — 

 at least as much salt as those of to-day, or of the Miocene which 

 gave the Polish deposits. Nor can we think that our Triassic 

 salt deposits, or the German Permian, came from oceans richer 



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