FORAMINIFERA 135 



very tiny creatures which live in the sea because 

 they inhabit shells, which are pierced all over 

 by numbers and numbers of still tinier holes. 



These foraminifera are so very small that 

 numbers of them can live in a single drop of 

 water! Yet, strange to say, all the chalk in the 

 world is made of their shells ! For in days of 

 old thousands and thousands of years ago 

 they were found in the sea in millions of millions 

 of millions. And as they died their empty shells 

 sank down to the bottom of the sea in such 

 enormous numbers that at last they formed a 

 layer hundreds of feet thick. Then suddenly 

 one day there came a great earthquake, and a 

 great deal of this vast layer of shells was forced 

 up above the surface in the form of what we 

 now call chalk. So that "the chalk cliffs of old 

 England " are really made of nothing but shells, 

 so very small indeed that you cannot see them 

 without the help of a very strong microscope ! 



There are a great many different kinds of 

 foraminifera. But if you look at them through 

 a good microscope you will always see that 

 their shells are pierced by the tiny holes from 

 which they take their name. 



