56 FORAMINIFERA 



By carefully washing a specimen of chalk 

 from the top layer in a chalk cliff many 

 varieties may be obtained. The clays also 

 of the Lias and Oolite contain many exquisite 

 representatives of the foraminifera. 



The original photograph from which the 

 illustration (Fig. 10) was taken is 40 times 

 the diameter of the tiny fossil marine 

 shells represented. A 2-inch objective was 

 used ; the focal distance was 84 inches ; 

 and the time of exposure was 15 

 minutes. 



