^^"^ ZOOGENESIS '^^^'^ 



time — are often found in ancient beach deposits. If 

 the remains lie in quiet water or at a depth below the 

 effect of waves the fossils that we find may be as per- 

 fect as the corresponding parts in living animals. 



Many sea animals and plants die and are buried in 

 the place in which they lived. For example, corals 

 (fig. 80, p. 143) and other reef forming animals and 

 plants are sometimes killed by changes in temperature 

 or depth or by some other cause or smothered by mud 

 and sand. 



Incredible numbers of fossil fish are found in thin 

 layers of rock or other deposits in California and else- 

 where. In some cases these probably were killed by 

 stranding in shallow bays into which they had been 

 driven by their enemies. 



Similar calamities are not infrequent at the present 

 day. In August, 192.5, I was so fortunate as to wit- 

 ness one at Manchester, Massachusetts. Immense 

 numbers of small herring ran into the little harbor 

 where by the falling of the tide they were stranded on 

 the mud flats. These they almost completely covered 

 — indeed in some places they lay two or more layers 

 deep. The weather was hot and they decomposed 

 with great rapidity. Their decomposition fouled the 

 water and this killed the larger fish, pollack and hake, 

 that had originally chased them in. 



If these had been covered with mud and buried 

 before decomposition had progressed too far, they 

 eventually would have formed just such a thin layer 

 of fossil fish as we find in the rocks. 



Fish are also destroyed wholesale in another way. 



[95] 



