14 



A. P. COLEMAN 



extended to cover the most ancient formations of the Old World 

 also. 



Though the Keewatin and Grenville series are the oldest known 

 formations in America, it is evident that they do not take us back 

 to the commencement of geological time, since they include 

 clastic sediments that imply the weathering and erosion of pre- 

 vious rocks before they were spread out on the sea bottom. We 

 have extended our outlook much farther into the past, but there 

 is still an impenetrable background beyond. We shall perhaps 

 never be able to say "in the beginning"; but we may safely say 

 that there is no hint of a molten earth in process of cooling down. 

 If the earth was ever hot it had so far cooled down before the 

 oldest known rocks were formed as to allow air and water and life 

 to do their work in the world very much as they do now. If the 

 earth ever passed through a period of great heat it was at a time 

 too remote in the past to leave a geological record or to have any 

 special interest for the geologist. 



