76 THE EARTH. 



fossil remains in the chalk are very numerous and are all of 

 a marine character, the ammonites (fig. 28), belemnites, and 

 other cephalopods, were very prevalent, as were the 

 various Echinodermata, as the Hemicidarus intermedia 

 (fig. 29), together with numerous univalve and bivalve 



FIG. 29. ECHINUS (Hemicidarus intermedia, Chalk). 



mollusca, various Crustacea, fish and reptiles. There was 

 some considerable wonderment a few years ago expressed at 

 the skeletons of men being found in the chalk at Gruadaloupe ; 

 but it has been ascertained that this chalk is a modern 

 formation, being produced by the sea washing and disinte- 

 grating the adjacent coral reefs, and depositing a fine white 

 sediment of broken coral on the shore which can hardly be 

 distinguished from ancient chalk ; the same process is 

 taking place at the Bermudas and other islands of the 

 West Indies. 



In many places the chalk strata contain single lines of 

 flints, running for miles parallel to the layers of chalk ; these 

 flints consist of almost pure silica, and it has been, matter of 

 wonder how they got there, but on considering how slowly 

 the deposition of chalk must have taken place, from the 

 formation and death of millions of minute creatures, and 

 that it was once the bottom of a deep sea, the disposition of 



