144 ROCHESTER ACADEMY OF SCIENCE. 



was later cut by man the canal that made Rich's Landing (now 

 Zarges) the port of entry for sailing boats in the days of the early 

 settlement. It is this artificial channel beside which the name 

 "Irondequoit River" is engraved on the topographic map, but the 

 Brighton-Penfield townline follows the natural tortuous stream 

 which still carries the main flow. 



The question confronts us, why should the river have been held 

 so rigidly in its place at the three pivotal point, .r, 3' and c, just 

 as it is at Zarges Wills, while permitted to freely meander into the 

 soft silts elsewhere between. Some efficient obstruction must have 

 served as the vise, for this is not the normal behavior of streams 

 engaged in valley-widening, in which the meanders pursue each 

 other steadily down the valley and widen all parts alike. Here then 

 is evidence that at these three points the stream encountered barri- 

 cades in the days when it was more actively corrading. These bar- 

 ricades are now eft'ectually concealed by the return of Ontario 

 waters raising the level of the marshes, but it is easy to ascribe 

 them to the buried northward continuations or declining ends of the 

 drumloidal flutings of the till whose summits are seen not far to 

 the south, along Blossom Road. For the easternmost one this rela- 

 tion was demonstrated by intervening till exposures at the State 

 Road, now grassed over. It is unnecessary at this time to go further 

 into the details of meander work of an intricate and somewhat ex- 

 ceptional nature to be found in this two mile stretch, since our 

 general conclusions are not involved. The scale of the map is too 

 small to show them well. 



The section below Palmer's Glen re(|uires no special analysis. 

 That to the south of Zarges presents many instances of meander 

 work, but nothing of ])articular moment save the long tongue pro- 

 jecting obliquely into the valley from just northwest of Penfield. 

 This has not been visited and its message is unknown, but it can- 

 not be a rock rilx 



IVurk of the Ontario zvatcrs. The waters of the present Bay 

 are those of Lake Ontario. The shallows at its two ends are con- 

 structional i)latforms in this water-level, the one a delta-filling of 

 the Irondequoit continuous with its marshes, the other a barrier- 

 beach accessory as exj^lained beyond. About its shores minor wave 



