94 LECTURE VII. 



which we tread. I should be sorry to state any- 

 thing to you without some proof of what I said. 

 It is easy, therefore, to show you that these almost 

 invisible shells have had to do with the con- 

 struction of the surface of the earth. Take, for 

 example, the neighbourhood of Paris. The 

 chalky substance about it is in some places so 

 filled with these shells, that a square inch 

 from one of the quarries contains something like 

 58,000 of them, and that in beds of great thick- 

 ness and of vast extent. This would give an 

 average of many millions of millions in the 

 square yard. Now, as all Paris and the towns 

 and villages of the neighbouring districts are 

 built of the stone quarried from this deposit, 

 it is evident, without any exaggeration, that 

 the capital of France and all the neighbour- 

 ing towns are constructed principally of these 

 little shells. Indeed, the chalk of our own dear 

 country, " the white cliffs of Albion," which you 

 all so well know, and which throughout is of 

 such vast thickness, contains myriads upon my- 

 riads of these interesting shells. 



But I shall tire you if I proceed further on 

 this subject. Be quite sure that I have the 

 authority of some of our best naturalists for 



