I06 FACTS AND FANCIES 



circulated * I have endeavored to present its 

 details in a popular form to general readers. . 



Geological investigation has disclosed a great 

 series of stratified rocks composing the crust 

 of the earth, and formed at successive times, 

 chiefly by the agency of water. These can 

 be arranged in chronological order; and, so 

 arranged, they constitute the physical monu- 

 ments of the earth's history. We must here 

 take for granted, on the testimony of geology, 

 that the accumulation of this series of deposits 

 has extended over a vast lapse of time, and 

 that the successive formations contain remains 

 of animals and plants from which we can learn 

 much as to the succession of life on the earth. 

 Without entering into geological details, it may 

 be sufficient to present in tabular form (see p. 

 107) the grand series of formations, with the 

 general history of life as ascertained from them. 



In the oldest rocks known to geologists — 

 those of the Eozoic time — some indications of 

 the presence of life are found. Great beds of 

 limestone are contained in these formations, 

 vast quantities of carbon in the form of graph- 

 ite, and thick beds of iron-ore. All these are 



* Story of the Earthy Origin of the Worlds Chain of Life in Geokg- 

 teal Time. 



