82 F. B. TAYLOR—ORIGIN OF GORGE OF WHIRLPOOL RAPIDS. 
10,000 or 12,000 years.* There is, as pointed out above, plausibility in this 
hypothesis, if we base our judgment on what we can learn from the study 
of the gorge characters alone ; but we can not, consistently with true scien- 
tific principles, ignore or fail to make the most effective use of the powerful 
light which the lake history throws on the Niagara problems. Those who 
have strong predilections for short postglacial time, however, have had 
much comfort from this hypothesis; so much, indeed, that they seem un- 
conscious of the decisive bearing of the lake history. 
Saint Davips GoRGE 
In discussing the Saint Davids gorge it seems to be very generally con- 
*In his adyoeacy of the 7,000 to 10,000 year estimate, Mr Warren Upham rests the case for short 
time on grounds which appear to be erroneous and indefensible. In a recent paper by him on the 
‘Origin and age of the Laurentian lakes and of Niagara falls”? (Am. Geologist, yol. xix, Sept., 1896, 
p. 176) oceurs the following passage: ‘“‘ The whole time of existence of lake Agassiz, as estimated 
by comparison of its shore erosion and beach accumulation with those of lake Michigan and others 
of the Laurentian lalkes since the departure of the ice-sheet, appears to have been about 1,000 years. 
In comparison with this we may confidently assert thatif any outflow passed for a time over lake 
Nipissing to the Mattawa river, it could have done so only for a few decades of years.” 
The attempt to estimate the duration of lake Agassiz from the shore erosion and beach accumula- 
tion of lake Michigan can hardly lead to the result claimed. The estimate of 7,500 years by Dr 
Edmund Andrews (‘“‘ The North American lakes considered as chronometers of postglacial time,” 
Trans. Chicago Acad. Sci., vol. ii, 1870) is often quoted ; but while Dr Andrews took account of the 
abandoned beaches that lie above the present lake level, he made no allowance for the long time 
that the lake stood at levels below the present. He had no data for such allowance. The fact 
was not then known that the lake had stood at lower leyels—50 to 100 feet lower on the shore of 
Illinois during all the time of lake Algonquin, and of Nipissing Great lake, and there is reason to 
believe that it has been slowly rising against the land since the beginning of the Champlain uplift 
when the discharge of the upper lakes shifted from north to south, and possibly for a considerable 
time before. A rising lake favors the most rapid and effective wave work on its shores. Taking 
Dr Andrews’ own estimate and adding these other factors to it, as we must do, it will be necessary 
to multiply Dr Andrews’ figures by at least three and possibly more. 
In the article referred to (p. 175) Mr Upham quotes Bell and Barlow, of the Canadian Geological 
Survey, as opposed to the hypothesis of the North Bay outlet, and as ‘stating that they find no 
evidence of a great river there.” These statements were made three or four years ago. Since then, 
in October, 1896, Dr Bell, with the writer, saw some of the evidences of the great river’s action at 
both North Bay and Mattawa. On hearing the evidences found, Mr Barlow, while adhering to his 
original statement, qualified it by saying that during his work in the Mattawa valley his attention 
was centered mainly on other matters, and he did not take particular notice of Pleistocene features. 
Mr Gilbert visited North Bay in September, 1887, and descended the Mattawa valley to the lower 
part of Talon lake. In “The history of the Niagara river” (the substance of an address at Toronto 
in August, 1889) he says: ‘Such data as I have at present incline me to the belief that for atime 
the upper lakes did discharge across the Nipissing pass” (page 72). Professor Wright and party 
visited North Bay, and also ascended the lower end of the valley from Mattawa over 8 miles, or to 
the mouth of the Amable du Fond river, in the summer of 1892; and, not knowing of Mr Gilbert’s 
earlier visit, reported the discovery of the outlet river’s bed and the confirmation of Mr Gilbert’s 
hypothesis. (‘‘ The supposed postglacial outlet of the Great lakes through lake Nipissing and the 
Mattawa river,” Bull. Geol. Soc. Am., vol. 4, 1892.) Between 1893 and 1896 the writer visited the 
Mattawa valley four times and spent altogether about three weeks studying the old river bed. Last 
autumn Professor W. M. Davis and Mr J. M. Boutwell spent half a day at North Bay and saw some 
of the marks at the head of the channel. Besides these named, no one else, so far as Known, has | 
looked for the bed of the old outlet river. Mr Upham says that if the discharge of the upper lakes 
ever went over the Nipissing pass ‘‘it could have done so only for a few decades of years.’ In view 
of the facts stated above, it would seem wiser for Mr Upham, who can not quote a single authority 
_ for his position, and who has never seen the two principal phenomena, neither the Nipissing beach 
nor the old river bed in the Mattawa valley, to suspend judgment for the present. 
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