Spencer — Great Canyon of the Hudson River. 11 



uted to submarine rivers. By this the hypothesis of a great 

 elevation of the continent was avoided. There seems nothing in 

 its favor beyond the occurrence of river valleys at great depth, 

 and some floating debris on the sea. As Prof. N. S. Shaler 

 says, subterranean channels must be formed above the base 

 level of erosion; and the establishment of such must precede 

 that of submarine rivers, which soon lose their effectiveness. 



Can the question of canyons be cavalierly disposed of by 

 calling them faults ? The level continental shelf is covered 

 with Tertiary sands and clays, such as would not favor an open 

 fault theory. The submarine topography on both sides is 

 identical, suggesting not the slightest disturbance to leave an 

 open fault, nor is such shown on the land adjacent. Joints and 

 faults may locate valleys, but the submarine shelf is only a 

 new plain prolonging the Hudson valley, which in slowly 

 rising would force the water to follow the lowest course. The 

 fault theory is not supported by the Great Valley of the 

 Appalachians, extending for a thousand miles, with a breadth 

 of from 20 to 40 miles, ^nd it is in a region abounding in 

 fault ; yet the valleys, as have long since been shown by 

 Professors Lesley and Dana, and others, are those of denuda- 

 tion and which I have confirmed in Georgia. Even the gorge 

 of the Delaware Water Gap, where more than a tyro 

 might be pardoned for suspecting a fault left open, is not 

 such according to Professor Lesley and Mr. Chance the geo- 

 logical surveyor of it. The submarine canyon of the Hudson, 

 which is double, the inner the more sinuous, does not lie 

 in a direct line, but turns twice at right angles within a 

 distance of a dozen miles, and below, it widens into a 

 fan-shaped valley. Hansen has described many submarine 

 valleys in the continental shelf of Norway and about Ice- 

 land,- and does not find it necessary to call in the existence 

 of faults, and .even where my evidence has not been full 

 in treating deep submarine valleys, he thinks there is no 

 other feasible explanation, than that the valleys are sunken 

 land features (page 192). Nor will those who appeal to Sir 

 A. Geikie find much comfort in faults. He says : — " To many 

 geologists the mere existence of a valley 'is evidence of the 

 presence of a fault," and that " in every case actual proof of a 

 fault should be sought for in the tectonic structure of the 

 ground." " In the vast majority of cases in Britain valleys 

 have no connections with faults." From its forms and its 

 associations I think we can dispense with the idea of a fault- 

 made rift, unaffected by atmospheric action ; and furthermore, 

 this is not in the region of apparent great tectonic disturbances, 

 but one of remarkable simplicity since in Cretaceous times. 



Finally I know of no other reason for appealing to faults as 





