:JH2 The Americait Geologist. October, 1896 
'*U. The Whirl i>ool8t. David's Chiuiiiel. G. K. Gilhkrt. When 
Hall and Lyoll visited the Whirlpool in 1841 and laid the foundation for 
its scientific interpretation, they differed notaVjly as to the character of 
the old channel they discovered. Hall thought it comparatively shal- 
low. My own study, which has been somewhat extended and has in- 
eluded a to[)ographical survey, sustains the view of Lyeil. 
Hall's opinion was based on the occurrence of rock in the bed of 
Bowman creek, a tributary of the Whirlpool. Bein;; surrounded by 
forest, and not having the aid of a good map, he made the easy mistake 
of supposing Bowman ravine to traverse the middle of the drift mass 
llUiug the channel, whereas it really follows the southwest margin ; and, 
where the creek trenches on the side of the buried channel, he thought 
the bottom was exposed. Claypole and Spencer afterward repeated his 
observation and inference. 
My study also confirms the observations of Lyell and Belt that the 
drift filling the old channel is visible in situ down nearly to the margin 
of the Whirlpool, instead of being a mere veneer of landslides as report- 
ed by Spencer. 
The course of the old channel between the Whirlpool and St. David's 
is now fairly well outlined. The southwest wall has been traced by 
-means of outcrops of Niagara limestone through nearly half its length. 
The northeast wall is fixed at one point by an outcrop and at a second 
]ioint by means of two deep wells, one of which penetrates drift only 
while the other encounters rock. 
From a study of the configuration of the Niagara gorge above the 
Whirlpool, it appears, on the whole, probable that the ancient gorge 
4 whether preglacial Or interglacial) ended two or three hundred yards 
above the Whirloool ; but Pohlman's theory that it extended to the 
Whirlpool rapids is not disproved. 
30. Profile of the Bed of the Niagara in its Gorge. G. K. Gilbert. 
In the pool between the cataract and the Whirlpool rapid a number of 
soundings were made by the United States Lake Survey, the greatest 
recorded depth being 189 feet. At the mouth of the gorge a depth of 
96 feet was determined by the same corps. At most intervening points 
direct measurement is prevented by strong currents. To supplement 
the soundings, I have made indirect measurements in four places, using 
a method first suggested by Taylor. At each place the width of the 
stream and the velocity of the central part of the current were measured. 
The simultaneous volume of flow was computed from the hight of water 
at the head of the river, as shown by the United States engineer gage at 
Biiffalo, the computation being based on discharge measurements made 
some years ago by U. S. engineers, near the International bridge. The 
depth was then derived by the following formula: 
15 Volume 
Central depth — g Qgjjj^gl yg,jjj.ijj. X width. 
The depth thus computed along the Whirlpool rapid was 35 feet; at 
the outlet of the Whirlpool, 50 feet ; opposite Wintergreen flat, 35 feet ; 
and below Foster flat, 70 feet. Some allowance should be made for the 
