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-sised 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- 
