Animals Before Man 



loss of life among animals much higher than 

 itself.* 



The deposits of Ohio and Indiana are 

 thought to have had a different origin. Dr. 

 Dall has noted the habit of certain fishes 

 which exist in vast numbers of frequenting 

 certain areas, where they eject the broken 

 shells of mollusks, corals, barnacles, and other 

 creatures which they have cracked, swallowed, 

 and cleansed of their soft tissues by digestion. 

 Some areas of the sea-bottom consist almost 

 wholly of this material, nearly every piece of 

 which bears the tooth-marks of a fish.f 



And this process went on in the past, even 

 as we know it to be going on now, with the 

 result that very considerable beds have been 

 formed by the work of hungry fishes. 



From Scaumenac Bay, Canada, have come 

 some very beautiful specimens of the armor of 

 Bothriolepis, flattened down, to be sure, but 

 with every plate in position, and from these it 



*See the American Naturalist for March. 1902. 



\ Dall. Deep-Sea Mollusks and the Conditions under which 

 they Exist ; being the Annual Address of the President of the Bio- 

 logical Society of Washington, delivered November 16, 1889. 



94 



