314. —sL. ‘Agassiz on Animals in Geological Times. 
of coast along the western shores of the American continent, 
the state of New York only. (See above the results of Professor 
Adams’s investigations upon the coast of Panama.) 
t is a most unexpected and very significant coincidence that 
the late admirable investigations of Elie de Beaumont upon the 
mountain systems, have led him to the recognition of nearly ten 
times as many periods of great disturbance in the physical con- 
stitution of the earth’s surface, as he himself knew twenty-five 
years ago, each attended by the upheaval of as many mountain 
chains, differing in their main direction. The investigations 
of paleontologists having an entirely different character, an 
founded upon facts which until recently have apparently had only 
a remote connection with the other series of phenomena, have 
nevertheless brought them at about the same time to like concla- 
sions respecting animal life, showing that the periods of disap- 
pearance and renovation of organized beings upon earth, have 
been much more frequent than could be supposed even ten years 
ago, each set having probably been characteristic of one of those 
long periods of comparative rest, intervening between two great 
successive geological cataclysms. ; 
What is true of Mollusca, may be said of all other classes. 
Among Radiata, are not the coral reefs of the paleozoic ages as 
rich in species as any coral reef of the Pacific? Let us even 
compare the most extensive list of corals yet given as belonging 
to any circumseribed locality,—those of the Red Sea as described 
by Ehrenberg,—those of the Feejee Islands as described by Prof. 
J. D. Dana,—and let us inquire whether the palzozoic rocks of 
the state of New York do not show as great a variety and as 
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