IN HIGHER PEOPLES 85 



forming a reef at that particular place and com- 

 pelling the Ohio river to stumble over it, lived and 

 died in that far off time when Indiana and Ken- 

 tucky formed a part of the floor of the Mississippi 

 Sea. 



Now, it is not so well knoA\Ti, but it is a fair 

 inference, that much of what is now water surface 

 was once land surface. We mine coal under the 

 sea in some places. And I suppose that if we 

 could only get at them we would find many things 

 in the lands under the sea that would be useful 

 to us land animals. Maybe, sometime, when we 

 have exhausted the stores of the land, we shall get 

 so hard up or so skilled that we shall be able to 

 get at these drowned treaures beneath the oceans. 



We knoiv that there have been many changes in 

 the geography of the earth in the past — that the 

 geography of the earth a million or ten million 

 years ago was not what it is today. We know 

 that Africa was joined to Europe at Gibraltar un- 

 til rather recent times in the history of the earth, 

 and that Asia and North America were united at 

 Behring Strait. 



Geologists say that North and South America 

 have been separate continents during most of 

 their geological history. The Isthmus of Panama 

 is very recent, geologically speaking. There are 

 reasons for believing that before South America 

 was joined to North America it was connected 

 with Africa and even Australia, forming a great 

 Antarctic continent. 



