as illustrating the Geology of North America. 1 7 



parts of the world also, where the superficies is found to possess 

 a similar secondary character. This being the necessary re- 

 sult from our inquiry, no one will probably deny that its bear- 

 ing upon the science of geology is most important; and that, 

 in fact, it involves a train of reasoning which must powerfully 

 influence the theories of that most interesting branch of study. 

 It has been already stated that the distance from the fall to 

 Queenston Ferry, where the river has resumed its more tran- 

 quil and navigable course, is about seven miles, or 37,000 feet; 

 and if we divide this distance according to the data already 

 stated, or at the rate of 4? feet per annum, we find that a little 

 more than 9000 years would be necessary to complete the 

 section as we now find it. It is scarcely necessary, however, 

 to point out that such calculation would not be fairly stating 

 the facts of the case. As we now see the fall, we find that it 

 has attained within 50 perpendicular feet of the summit level, 

 and that it is now, consequently, acting upon a vastly greater 

 resisting body than was at first opposed to it, in the com- 

 mencement of its labours. By a reference to the section, it 

 will be seen that the height of the fall must necessarily have 

 progressively increased, from the very bottom at D, where it 

 begun as the lower portion of a mere supeifcial rapid, up to 

 its present elevation of 160 feet; and as the acting force has, 

 at all times, been the same, while, on the contrary, the op- 

 posing one has been greatly less, it would by no means de- 

 monstrate the truth if we took the present rate of action as a 

 fixed point to calculate from. We arrive at this conclusion by 

 a natural and obvious line of reasoning, which we should not 

 hesitate to apply in the case of any great artificial work. In 

 this difficulty it naturally occurs to the mind to try the ques- 

 tion by the most approved system of chronology, and it there- 

 fore only remains to divide these 37,000 feet by the 4000 years, 

 more or less, which are generally supposed, even by many 

 geologists (and Cuvier amongst the number), to have elapsed 

 since the period of the last great catastrophe (geologically 

 speaking), or the Mosaic Deluge (if we trust to the evidence 

 of Scripture). We find, then, that by this process a rate of 

 action, amounting to about 9 feet per annum, would exactly 

 bring us to this great and interesting point', and it only re- 

 mains for those who are accustomed to such calculations of 

 solid measurements to say, whether 9 feet of general average 

 over the whole space may be admitted to be a fair medium 

 amount of action. If, by ma- a 37,000 feet. 



nual or other labour, 4- feet are § r^HT" - _ I 



removed per annum at A, a cube " ^ -t— = ^fst— I B 



of the same dimensions would require a little more than 9000 

 Third Series. Vol. 5. No. 25. July 1834. D 



