THE ANTIQUITY OF MAN 221 



yield more definite results to careful study." 

 We ought, therefore, to be able to secure valu- 

 able information from a consideration of the 

 facts obtained over a number of years study of 

 the conditions. 



Lyell visited the falls in 1842, and made a guess 

 admittedly a guess, though it has often been 

 quoted as if it were a carefully thought-out 

 opinion that the rate of erosion could not be 

 more than one foot per annum, and probably 

 would not be more than a third of this. This set 

 geologists to work, and during the sixty-five 

 years which had intervened between the date 

 mentioned above and 1907 it turned out that the 

 rate of erosion has been a little more than five 

 feet per annum, that is, more than five times 

 LyelPs maximum, and more than fifteen times 

 his minimum. "So that, if the same forces had 

 been at work continuously in the past that are 

 operative at the present, Niagara River would 

 have eroded the whole gorge in seven thousand 

 years," says G. F. Wright (p. 178), and proceeds 

 to show where the falls were at different points 

 of history, terminating by the statement that " the 

 beginning of the Falls at Queenston occurred 

 only a short time before the building of the 

 great pyramids and the expedition of Sargon 

 from Babylonia to the shores of the Mediter- 

 ranean about 3,800 B.C." From this and a vast 

 amount of other evidence, for which the reader 

 must be referred to his book, he concludes that 

 the epoch the entire glacial epoch does not 

 .extend to more than 80,000 years (p. 200), and 



