246 THE HISTORY OF THE NIAGARA RIVER 



Graphic methods are ill adapted to the coiniminication of qualified or 

 indefimte stateinents. By the aid of a map one can indicate definitely 

 the relation of Albany to other places and things, but he cannot say 

 indefinitely that Albany is somewhere in eastern New York, nor can 

 he say, with qualification, that it is probably on the Mohawk River. 

 For thivS reason I have decided to publish these two maps only after 

 hesitation, because I should greatly regret to produce the impression 

 that the particular configuration of lakes and outlets here delineated 

 has been actually demonstrated. The facts now at command are sug- 

 gestive rather than conclusive, and when the subject shall have been 

 fully investigated it is to be expected that the maps representing these 

 epochs will exhibit material differences from those I have drawn. The 

 sole point that 1 wish to develop at this time is the probability that dur- 

 ing a portion of the history of the Niagara River its drainage district — 

 that area from wliich its water was supplied — was far less than it is at 

 the present time. There is reason to believe that during an epoch 

 which may have been short or long— we can only vaguely conjecture — 

 the Niagara was a comparatively small river. 



The characters of the gorge are in general remarkably uniform from 

 end to end. Its width does not vary greatly ; its course is flexed but 

 slightly ; its walls exhibit the same alternation of soft and hard rocks. 

 But there is one exceptional point. Midway, its course is abruptly 

 bent at right angles. On the outside of the angle there is an enlarge- 

 ment of the gorge, and this enlargement contains a deep pool, called 

 the Whirlpool. At this point, and on this side only, the material of 

 the wall has an exceptional character. At every other point there is 

 an alternation of shales, sandstones, and limestones, capped above by 

 an unequal deposit of drift. At this point limestones, sandstones, and 

 shales disappear, and the whole wall is made of drift. Here is a place 

 where the strata that floor the plateau are discontinuous, and must 

 have been discontinuous before the last occupation of the region of the 

 glacier, for the gap is filled by glacial drift. 



Another physiographic feature was joined to this by Lyell and Hall. 

 They observed that the cliff limiting the plateau has, in general, a very 

 straight course, with few indentations. But at the town of St. David's, 

 a few miles west of Queenston. a wide flaring gap occurs. This gap 

 is partly filled by drift, and although the glacial nature of the drift 

 was not then understood, it was clearly perceived by those geologists 

 that the drift-filled break marked the position of a line of erosion 

 established before the period of the drift. Putting together the two 

 anomalies, they said that the drift-filled gap at the Whirlpool belonged 

 to the same line of ancient erosion with the drift -filled gap at St. 

 David's.* Their conclusion has been generally accepted by subsequent 

 investigators, but the interpretation of the phenomena was carried 



* Travels in North America. By Charles Lyell. New York, 1845. Vol. ii, pp. 

 77-80. Natural History of New York. Geology, Part iv. By James Hall, pp. 389-390. 



