J. W. SPENCER— THE IROQUOIS SHORE. 493 



shore features. It was afterward announced by l>r. Spencer that he had suc- 

 ceeded in tracing the shore line several miles farther eastward than I had seen it' 

 and tins announcement stimulated me to renew my search, [n the autumn of 

 ls'.io I revisited the region in company with Mr. Warren Upham. Starting al 

 Adams Centre, we ran a line of levels past Watertown to cape Rutland, a point 

 where the shore features are clearly exhibited at the western margin of the sand 

 plain. This point, winch had previously been missed by me, was discovered by 

 Dr. Spencer. The shore-line there has an altitude of 730 feet. Thence we carried 

 our level line to the eastern margin of the sand plain, where we found a rock sur- 

 face thinly covered witli drift and well adapted to the preservation of a shore 

 record. Over this surface we made search through a range of altitudes extending 

 50 feet below the horizon, where shore features were to be expected, and an 

 equal distance above. Our results were purely negative. The drift seemed not to 

 have been disturbed by the waves. 



About the same time Dr. Spencer also returned to the held and carried his ob- 

 servations farther eastward and to higher levels. The results he communicated 

 to me* accorded so poorly with mine that I proposed a joint excursion, hoping 

 that if we saw the phenomena together we might come to view them in the same 

 way. The hope was not realized, but our journey was nevertheless fruitful. It 

 served to prove that we differ widely as to the criteria by which shore ridges and 

 shore terraces are distinguished from ridges and terraces of other origin. In 

 the series of localities to which Dr. Spencer conducted me, from Natural Bridge to 

 Fine, I saw but a single ridge that seemed to me to simulate a shore ridge, and the 

 associated phenomena made me confident that that was a case of simulation only, 

 instead of a shore-line or group of shore-lines 1 saw a magnificent series of kames 

 and pitted plains, occupying the valleys of a rugged district, and associated with 

 channels of temporary discharge from one valley to another. The series is too 

 complex to be analyzed folly during a rapid reconnoissance, but all its elements 

 announce the margin of an ice field, and none of them announce the margin of a 

 lake. [ am still of opinion that the Iroquois shore-line ends at cape Rutland, and 

 that the Iroquois water was bounded on the northeast by a wall of ice on which 

 the waves could make no permanent record. 



A lew words as to Dr. Spencer's second paper: The channel features at the col 

 have greater extent than he mentioned. The rock floor is swept clear of all drift 

 except a few bowlders of greal size. North of the col one passes from the rock 

 floor to the gravel terrace of the Black river valley without notable change of 

 altitude. South of the col one descends toward the Mohau k for two miles or more 

 before he finds the rock floor covered by drift or alluvium. The vertical descent in 

 this distance is not les< than 60 feet. These features appear to accord with the 

 theory thai a river descended southward from the col far better than with the 

 theor) that the col was swept clean by tidal currents. 



It is true thai there are terraces south of the col accordant in height with the 

 -real terrace north of it. hut the assumption that these are shore terrace- is gratui- 

 tous. Terraces originate in many way-, ami it is not always easy to determine the 



origin of individual examples. The terrace on which Dr. Spencer bases his argu- 

 ment was not well displayed nor was it carefully examined. I noted no feature 



* Tin--" results nre briefly mentioned ■!-" in tm .To urn. Sei , 3d oeries, vol. \l. I8fl<), pp. 1 1 • 148, 



l.\ VI I Bi ii '■n.i Soi \m . Voi„ ::, I--.1 



