2GG rnYsicAL geography of the sea, and its meteokology. 



the mica in another, and the qnartz in a third, and then the 

 three brought together by some mighty power, and welded into 

 the granite rock for the everlasting hills to stand upon? or were 

 they, as they were formed of the chaotic matter, made into rock ? 

 Sea water is composed of oxygen and hydrogen, and its salts, 

 like the granite, also consist of gases and volatile metals. But 

 whether the constituents of sea water, like those of the primitive 

 rocks, were brought together in the original process of formation, 

 and united in combination as we now find them in the ocean, or 

 whether the sea was fresh " in the beginning," and became salt 

 by some subsequent process, is not material to our present pur- 

 pose. Some geologists suppose that in the Chalk period, when 

 the ammonites, with their huge chambered shells, lived in the 

 sea, the carbonaceous material required by these creatures for 

 their habitations must have been more abundant in its waters 

 than it now is ; but, though the constituents of sea water may 

 have varied as to proportions, they probably were never, at least 

 " since its waters commenced to bring forth," widely different 

 from what they now are. It is true, the strange cuttle-fish, with 

 its shell twelve feet in circumference, is no longer found alive in 

 the sea : it died out with the Chalk period ; but then its com- 

 panion, the tiny nautilus, remains to tell us that even in that 

 remote period the proportion of salt in sea water was not un- 

 suited to its health, for it and the coral insect have lived through 

 all the changes that our planet has undergone since the sea was 

 inhabited, and they tell us that its waters were salt as far back, 

 at least, as their records extend, for they now build their edifices 

 and make their habitations of the same materials, collected in 

 the same way that they did then, and, had the sea been fresh in 

 the interim, they too would have perished, and their family 

 would have become extinct, like that of the great ammonite, 

 which perhaps ceased to find the climates of the sea, not the 

 proportion of its salts, suited to its well-being. 



495. Cubic miles of sea salt. — Did any one who maintains that 

 the salts of the sea were originally washed down into it b}'- the 

 rivers and the rains ever take the trouble to compute the quantity 

 of solid matter that the sea holds in solution as salts ? Taking 

 the average depth of the ocean at three miles, and its average salt- 

 ness at 3i per cent., it appears that there is salt enough in the 

 sea to cover to the thickness of one mile an area of several millions 

 of square miles. These millions of cubic miles of crystal salt 



