1870.] 235 [Shaler. 



that a large part of the sediment falling on that floor (probably at 

 least one third of the mass) was the product of vertebrate animals. 

 This is clearly by no means a probable supposition. 



We know that some of the pteropod mollusks, forms which are 

 frequently abundant in the ocean at great distances from the land, 

 have a composition not materially different from that of bones. It 

 has even been stated, though I do not yet know by what authority, 

 that some of the marine algse contain a large per cent, of phosphate 

 of lime. The fact of the existence of this material in a number of 

 the inferior organizations of the sea makes it, in most cases, more 

 reasonable to account for the formation of extensive masses of phos- 

 phate beds by the deposition of the remains of invertebrate species, 

 than to suppose that they were accumulated by vertebrate animals. 



If the foregoing view of the process by which the phosphate beds 

 of South Carolina were formed be correct, then we may draw the im- 

 portant conclusion, important at least in an economic point of view, 

 that wherever the phosphate-containing marls of the South Atlantic 

 sea board lie in a position similar to that which they occup} r in the 

 vicinity of Charleston, the bed of nodular phosphate is likely to be 

 found. The United States Coast Survey is about undertaking a 

 careful examination of the region where it is likely that these beds 

 may be found. So that this important source of wealth, not only to 

 the States where it occurs, but to the whole country, may not want 

 for that aid in its development which it may reasonably be expected 

 the government should give. 



There can be no doubt that the area of the nodular phosphates is 

 much underestimated, though how great a part of the region where 

 they occur contains the material in workable quantities, may remain 

 a questionable matter. 



It seems likely that the peculiar advantages of these beds will ena- 

 ble them for a long time to control the market for phosphates, at 

 least in this country. They are over great areas, scarcely covered 

 by the soil, so that the labor of excavating is small. The beds are, 

 in most cases, remarkably accessible,, on account of the peculiar sys- 

 tem of lagoons which intersect the coast. Furthermore, the supply 

 lies in a region which, more than any other in the world, is likely to 

 require a large amount of fertilizing material of this character, to 

 balance the waste brought about by the exportation of raw agricul 

 turai products. 



