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re 
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ba 
— 
& 
3 
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ju 
me 
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for 
| calcium, The carbonate of lime present in the nodular phos- 
| __ phate, would be looked for, as the residuum of that belonging 
Process of its formationeis still in progress at many places on 
the Musquito coast. It is not unreasonable therefore, to ascribe 
the origin of our phosphatic formation partly to the same cause, 
at least under the modifications above pointed out. — 
A reason why the nodular layer is interrupted in its lateral 
extent may be, that the original surface, prior to its submer- 
sion, was not everywhere sufficiently above the sea-level to give 
tise to a soil abounding in organic matter. There probabl 
existed lagoons, whose bottoms were free from the phospha 
deposits, which, in some instances, may correspond to the 
_ Places where these are wanting, as w Tugi ; 
sand-layer, at Port Royal on St. Helena, Pinckney Island, and 
other localities, where the stratum of the nodular f 
appears to find its equivalent in this latter formation. ; 
