520 THE JOURNAL OF GEOLOGY. 



less alkaline and the conditions of chemical precipitation must 

 have been still more restricted. In time it might occur that pe- 

 lagic organisms should demand so much lime for circulation from 

 the water to calcareous algae, to herbivorous and then to carni- 

 vorous forms, and so back into solution, that lime could escape 

 from solution by precipitation only under exceptional conditions. 

 If it be true that the oceanic oozes, the muds of the Caribbean, 

 the mud-flats of Florida, and similar calcareous deposits in differ- 

 ent seas the world over, be wholly organic, then marine life has 

 locked up more lime than the continents could concurrently sup- 

 ply, and the balance is now turned against chemical precipitation. 

 But it has not always been so. 



Bailey Willis. 



