78 A RECORD OF TIME 



rock bears testimony that he was here and lived his 

 life and fought the ceaseless fight for existence* 



Then the record tells of cold too intense for animal 

 or vegetable life* For ages a continent of ice* seem- 

 ingly immovable but for ever moving* ground the 

 rugged fragments of rock into symmetrical boulders* 

 These are imbedded in hard clay* the accumulation 

 of a long era of glacial action* That the continent of 

 ice moved is shown by the worn and pulverised rocks 

 as well as by the continuous motion of the glacial ice 

 still remaining elsewhere* That it yielded to a warmer 

 era is shown by the abundance of animal and vege- 

 table remains in the supervening gravel and sand* 

 Here the shells are still preserved* and the remains 

 of some fifty species have been collected. Many are 

 remarkably perfect* 



The great majority of these species are now extinct, 

 but some of the Clams still survive* an evidence 

 of the limit of subsequent destruction* The climate 

 was milder than any that has been experienced in 

 this region during the present geological era* The 

 Osage Orange and other trees now indigenous to the 

 Mississippi and Ohio valleys are found in abundance* 

 A good-sized tree-trunk taken out was cut up and 

 used by a cabinetmaker, the few hundred thousand 

 years it had lain there under water* ice* and dry 

 earth* having served to improve rather than injure 

 it* The discovery of a Fish's head was a new revela- 



