38 LECTURES 



several geological horizons. Some have gone so far as to 

 say that they have been guided simply by the great 

 apparent age of the fossil remains of animals that for- 

 merly Inhabited the earth; that the mere fact of 

 such remains being converted into petrifactions must of 

 necessity have taken millions of years; that those esti- 

 mates are, in their estimation, still further supported by 

 the discovery in different parts of the world of entire 

 forests of enormous trees which at some other very re- 

 mote age were similarly fossilized. But those people to 

 whom I refer are quite wrong in the premises, and the 

 conception of the lapses of time in the world's history, as 

 arrived at by the geologist, is by no means based upon 

 any such data. Nor do we claim upon the other hand 

 that the time calculations as arrived at by the geologist 

 are to be considered correct beyond all peradventure of a 

 doubt; they may be hundreds of years or even thousands 

 of years wide of the truth; but, notwithstanding all that, 

 they never vitiate his right to state within certain bounds 

 the immense lapses of time that it has taken Nature to 

 bring about some of her results as they are revealed to us 

 in our study of the physical history of the world and 

 recorded in her geology. 



In order to illustrate my meaning permit me to present 

 you with one or two examples. A very simple one is the 

 calculation of the time it has probably taken for the 

 Niagara River to excavate its gorge. That feat is but one 

 of many thousands of Nature's chiselings, which has 

 been accomplished entirely within the scope of the pres- 

 ent epoch, and the computation of tbe time it has taken to 

 perform it is a matter of no great difficulty, as the physi- 

 cal factors of the problem are at our hand. The geolo- 

 gist tells us that he believes it to have been about 36,000 

 years. Now there is no difficulty in ascertaining the fact 

 that Lake Erie has an elevation of about 300 feet above 

 Lake Ontario, the former being terminated by an abrupt 

 escarpment of about 300 feet in height; and, from this 

 point, according to an eminent authority, "a narrow 

 gorge, with nearly perpendicular sides and 200 to 300 feet 

 deep, runs backward through the higher or Erie plateau 

 as far as the falls. The Niagara River runs out of Lake 

 Erie and upon the Erie plateau as far as the falls, then 

 pitches 167 feet perpendicularly, and then runs in the 

 gorge for seven miles to Q.ueenstown where it emerges on 

 the Ontario plateau. Long observation has proved that 

 the position of the fall is not stationary, but slowly 

 recedes at a rate which has been variously estimated 



