THE WOELD WITHOUT A BACKBONE. 235 



Here were banks of polyp corals each little creature planted 

 in his cup and expanding his petal-like tentacles in the life- 

 giving sunlight. Over this slope of animated stone crawled 

 lazy sea-snails grazing on the tentacled growths then beginning 

 a work of coral-building which the Florida reefs witness still 

 in progress. 



The cycles of Cambrian and Silurian time swept on and 

 came to an end. The history of life showed no departure 

 from the fundamental types with which that history was in- 

 augurated. There were new species, new genera, some new 

 families, scarcely a new order or class. The changes were so 

 slow that the world seemed finished, and finished for these 

 happy creatures that held possession of it. Yet an occasional 

 visitor from another world would have noted changes. The 

 Cordilleran Land had sunken step by step, and was even now 

 reduced to an archipelago. The Great Northern Land, on 

 the contrary, had risen step by step, till its southern limits 

 extended from Albany to Syracuse and Buffalo, and thence 

 to Detroit, Mackinac, Milwaukee, and Chicago. North of 

 this line lay the continental surface. A great island stretched 

 perhaps, from Sandusky to central Kentucky. These lands 

 were the empire of silence and desolation. Populous as were 

 the waters, here was no motion or sound of animated creature. 

 Sparse, dwarf tree-growths fringed the bleak horizon, but 

 flower and fruit, grass and herb, were yet unknown. The 

 sea, always jealous of the conquests made from his domain 

 continued to growl around the borders of the land, and pur- 

 sued industriously the work of reclamation of his ancient 

 slime. The wandering winds finding no fertile isle to fan or 

 sail to waft, confederated with the destroying waves wreaked 

 their anger on the crumbling shores and howled sullenly 

 through the vistas of the sparsely wooded plain. 



