1 68 THE MEANING OF EVOLUTION 



ican continent, with its developing animals and plants, 

 is tied up with the gradual shrinkage of this interior 

 sea. Slowly across the Canadian district, the Eastern 

 and Western lands became connected with each other, 

 while the waters progressively were pushed down the 

 continent, which was steadily growing from the east 

 and from the north, though less slowly from the west, 

 into this internal sea. To-day only the Gulf of Mex- 

 ico remains as evidence of the broad stretch that once 

 extended through to the Arctic Ocean and west be- 

 yond the present position of the Rocky Mountains. 



How this great Eastern backbone of the continent 

 was produced, what sort of animals lived while these 

 rocks were being formed, or whether this preceded 

 entirely the existence of life upon the earth, no man 

 to-day may surely say. In the oldest of the rocks 

 there are beds of graphite, from which lead pencils 

 are made. This substance is believed by the geolo- 

 gists to be, like coal, the remains of vegetable life. 

 But these early rocks have been so heated and baked, 

 so twisted and bent, that whatever forms of life they 

 once held are now obliterated, or so altered as to give 

 us no idea of what may have been their character. 



So far as anyone can now see, this past history is 

 wiped out forever and it will be impossible for men 

 ever to demonstrate the character of this early life. 

 Speculations, more or less certain, will arise. They 



