THE^SALTS OF THE SEA. 205 



ally formed in one heap, the mica in another, and the quartz in a 

 third, and then the three brought together by some mighty pow- 

 er, and welded into the granitic rock for the everlasting hills to 

 stand upon ? or were they made into rock as they were formed of 

 the chaotic matter ? 



575. 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 prim- 

 itive rocks, were brought together in the process of formation, and 

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

 er the sea was fresh " in the beginning," and became salt by some 

 subsequent process, is not material to our present purpose. 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. 



576. 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 companion, the tiny nautilus, 

 remains to tell us that even in that remote period the proportion 

 of salt in sea water was not unsuited 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 perish- 

 ed, 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. 



577. Did any one who maintains that the salts of the sea were 

 originally washed down into it by 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 



