In my investigations leading to “The Evolution of the Falls of Niagara” the most important problems were those bearing on the changing physics of the great cataract. To a relatively small extent the valleys buried beneath the drift produced effects, but that which was written on the features of the drift was only preliminary and should not be considered as a complete investigation of the subject, as lack of time did not permit of a full treatment. The river was regarded in a general way as postglacial for that region only. With those notes now amplified by more complete details and the features still impressed on my mind, a better description can be given of the changing Pleistocene formations in this locality than that previously published.
The peculiarities of the Whirlpool were first described by Lyell in 1841. He thought the Niagara River . . .