CHALK MAKERS, OR FORAMINIFERA. 51 



ceous period and the chalk mud of the Atlantic are 

 substantially the same." "Altogether, two slides, 

 one of washed-down white chalk, and the other of 

 Atlantic ooze, resemble one another so nearly that 



FIG. 10. GRAVESEND CHALK. 



it is not always easy for even an accomplished micro- 

 scopist to distinguish them." 



In order to remove all doubt as to the impression 

 he intended to convey, the same writer emphasises 

 this point subsequently, when he writes : " There 



E 2 



