Established by Edward L. Youmans
APPLETONS'
POPULAR SCIENCE
MONTHLY
EDITED BY
WILLIAM JAY YOUMANS
VOL. LV
MAY TO OCTOBER, 1899
NEW YORK
D. APPLETON AND COMPANY
1899
Copyright, 1899,
By D. APPLETON AND COMPANY.
THOMAS EGLESTON.APPLETONS' POPULAR SCIENCE MONTHLY.
JUNE, 1899.
NEW METHOD OF ESTIMATING THE AGE OF NIAGARA FALLS.
By G. FREDERICK WRIGHT.
Both the interest and the importance of the subject make itworth while to follow out every clew that may lead to the approximatedetermination of the age of Niagara Falls. During thispast season, in connection with some work done for the New YorkCentral Railroad upon their branch line which runs along the easternface of the gorge from Bloody Run to Lewiston, I fortunately cameinto possession of data from which an estimate of the age of the fallscan be made entirely independent of those which have heretoforebeen current. The bearing and importance of the new data can bestbe seen after a brief résumé of the efforts heretofore made to solvethis important problem.
Fig. 1.—Looking north from below the Whirlpool, showing the electric road at the bottomof the east side of the gorge, and the steam road descending the face about halfway tothe top.In 1841 Sir Charles Lyell and the late Prof. James Hall visitedthe falls together; but, having no means of determining the rateof recession, except from the indefinite reports of residents and guides,they could place no great confidence in the "guess," made by SirCharles Lyell, that it could not be more than one foot a year. Asthe length of the gorge from Lewiston up is about seven miles, thetime required for its erosion at this rate would be thirty-five thousandyears. The great authority and popularity of Lyell led the generalpublic to put more confidence in this estimate than the distinguishedauthors themselves did. Mr. Bakewell, another eminent Englishgeologist, at about the same time estimated the rate of the recessionas threefold greater than Lyell and Hall had done, which would reducethe time to about eleven thousand years.
But, to prepare the way for a more definite settlement of the[Pg 146]question, the New York Geological Survey, under Professor Hall'sdirection, had a careful trigonometric survey of the Horseshoe Fallmade in 1842, erecting monuments at the points at which their angleswere taken, so that, after a sufficient lapse of time, the actual rateof recession could be more accurately determined. In 1886 Mr.Woodward, of the United States Geological Survey, made a newsurvey, and found that the actual amount of recession in the centerof the Horseshoe Fall had proceeded at an average rate of about fivefeet per annum. The subject was thoroughly discussed by Drs.Pohlman and Gilbert, at t