174 Hillside. 



called Globigerina, and these have the power to extract 

 carbonate of lime from the sea-water, and to use it in build- 

 ing up the shells which cover them. These shells are full 

 of tiny holes or foramina, and from this circumstance the 

 group of animals to which they belong are called Foramini- 

 fera. Millions of these little creatures die every year, and 

 their shells, dropping to the floor of the ocean, form a kind 

 of mud, called Globigerina ooze. Samples of this ooze have 

 been obtained by means of dredging apparatus, and under 

 the microscope it has proved to be almost identical with 

 common chalk in structure. No doubt, in the far, far future, 

 these beds will be elevated above the sea-level, and form 

 solid rock. In this way, undoubtedly, most of our limestone 

 and chalk rocks have been formed. 



Scattered here and there through the chalk are numerous 

 remains of various sea animals fish-bones, sponges, sea 

 urchins, shells, etc. These were, when alive, made up 

 partly of organic and partly of mineral matter. After 

 death, the soft, organic parts decay, fine particles of car- 

 bonate of lime are deposited in their stead, and after a time, 

 an exact duplicate of the original animal, or part of an 

 animal, is formed, but made of carbonate of lime. The de- 

 posits of succeeding years and ages bury this deeply in the 

 ooze which was being deposited at the time it was formed. 

 Thus have many of our fossils been formed. In this way we 

 can peer a little into the dark recesses of the long ago. 



We leave the edge of the railway cutting, and, getting 

 over the fence, find ourselves on a sloping bank very similar 

 to the one on the other side. The sun has long since reached 

 its zenith, and is now rapidly westering, as we know by 

 the slanting shadows that fall across the bank. It is still 



