THE WORLD WITHOUT A BACKBONE. 233 



constitute tfie beginnings of those lands destined to endure to 

 our time. Very likely the upheaval was accomplished through 

 many partial upheavals widely separated in time. But we 

 can only contemplate the total result. When the Eozoic 

 jEon was ended, and the Palaeozoic JEon begun, there existed 

 on the American side of the world, the following outcrops: 

 1. The Great Northern Land, lying north of the St. Law- 

 rence and the Great Lakes, stretching in one direction to the 

 coast of Labrador, and in the other, over the region between 

 Hudson's Bay and the Mackenzie River to the Arctic Ocean. 

 This sent a tongue across the St. Lawrence, at the Thousand 

 Islands, and extended into the Adirondack Highlands. 2. 

 The Seaboard Land, lying east of the present Appalachians, 

 and reaching on the north to New England and on the south 

 to Alabama. 3. The Cordilleran Land, covering a large part 

 of the region west of the Great Plains stretching from the 

 crests of the eastern ranges of the Rocky Mountains into 

 California. Of its northern and southern extent we remain 

 in ignorance. Possibly this Cordilleran Land was more of 

 the nature of an archipelago than a continent. There were 

 smaller exposures of land, but we need not speak of them par- 

 ticularly. The rocks forming these continental nuclei are all 

 metamorphic. Between them and the rocks immediately over- 

 lying is an abrupt contrast. Why the process of metamor- 

 phism has been thus limited upward, has not yet been 

 explained. 



These lands were outstanding at the beginning of the 

 Palaeozoic ^Eon. All else was sea. I am quite ready to be- 

 lieve, however, that other lands existed, since consumed by 

 the erosions which sought to lay the foundations of newer 

 formations. On the remoter side of this upheaval was an 

 ocean barren, if we can believe it, of all forms of animal life. 

 On this side was an ocean which suddenly teemed with the 

 shapes of sensitive creatures already of high rank, and diver- 

 sified in nature, but strange and archaic in their structures 

 and aspects. This sudden advent of hordes of creatures of 

 diversified types of life has been relied on as evidence that 



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