18 ON A PIECE OF CHALK I 



and superposition of the stones of the Pyramids, 

 that these structures were built by men, has no 

 greater weight than the evidence that the chalk 

 was built by Grlcbigerina; and the belief that 

 those ancient pyramid-builders were terrestrial 

 and air-breathing creatures like ourselves, is not 

 better based than the conviction that the chalk- 

 makers lived in the sea. But as our belief in the 

 building of the Pyramids by men is not only 

 grounded on the internal evidence afforded by 

 these structures, but gathers strength from multi- 

 tudinous collateral proofs, and is clinched by the 

 total absence of any reason for a contrary belief; 

 so the evidence drawn from the Globigerince that 

 the chalk is an ancient sea-bottom, is fortified by 

 innumerable independent lines of evidence ; and 

 our belief in the truth of the conclusion to which 

 all positive testimony tends, receives the like 

 negative justification from the fact that no other 

 hypothesis has a shadow of foundation. 



It may be worth while briefly to consider a few 

 of these collateral proofs that the chalk was de- 

 posited at the bottom of the sea. The great 

 mass of the chalk is composed, as we have seen, 

 of the skeletons of Globig&rince, and other simple 

 organisms, imbedded in granular matter. Here 

 and there, however, this hardened mud of the 



size (which is about iinnjth), and no longer doubt that they 

 are produced by independent organisms, which, like the Globi- 

 gerince, live and die at the bottom of the sea. 



