348 A. P. COLEMAN — IROQUOIS BEACH IN ONTARIO 



up to 762 feet, and Lyell agrees with him in regard to some of them, 

 though not certain that all were really beaches. Later students of the 

 region have found only one well marked beach out of the supposed 

 series, the one now called the Iroquois beach. This was Roy's second 

 shoreline, which he places 208 feet above lake Ontario, his measurement 

 being about 30 feet above the real level. Lyell compares the beaches 

 which he saw to the parallel roads of Glen Roy,* but in the backwoods 

 behind the new town of Toronto he had apparently poor opportunities 

 to follow the supposed terraces and discover whether they were really 

 due to wave action. 



Both Roy and L}^ell had theories to account for the supposed beaches, 

 Roy imagining ranges of mountains to the south and east holding in a 

 great lake until the water slowly cut down its outlet and drained the 

 basin to its present level, while Lyell preferred to suppose that the 

 beaches were marine and formed when the land stood lower ; so that the 

 controversy as to the character of the water had already begun. 



To give in detail the literature which has grown up about this inter- 

 esting subject would take too long, and references to it may be found in 

 papers by Doctor Gilbert,f Doctor Spencer, J Professor Fairchild, § and 

 the present writer. || It may be said in a general way that Doctors Gil- 

 bert and Spencer, on the south and north sides of lake Ontario respect- 

 ively, worked out the elevation of a number of points on the beach and 

 proved conclusively that it is deformed, having been differentially ele- 

 vated toward the northeast. They published similar sketch maps of the 

 old shore, giving for the first time a clear idea of the area of the ancient 

 body of water, but they differed as to its character, Gilbert considering 

 it to be an ice-dammed lake with a well marked outlet past Rome and 

 through the Mohawk valley into the Hudson, while Spencer thought the 

 beach could be traced from point to point along the Adirondacks to the 

 east beyond the supposed ice dam, and hence must have been formed 

 at sealevel as an extension of the gulf of Saint Lawrence. 



In 1890 Professor Fairchild described the different levels into which 

 the beach is split to the north of the Rome outlet, as far as Watertown, 

 New York, and concluded that the warping of the old beach was largely 

 produced since Iroquois times. His report is accompanied by a map of 

 much larger scale than those hitherto published, but, as far as the north 

 shore is concerned, he merely reproduces Spencer's rough sketch, while 



* Lyell : Travels in North America, vol. ii, pp. 103-106. 



t Sixth Ann. Rept. Commissioners, State Reservation, Niagara, 1890, p. 67 et seq. 



t Trans. Roy. Soc. Canada, sec. iv, 1889, pp. 121-134, and Duration of Niagara Falls, p. 44 et seq. 



I Pleistocene Geol. Western New York, Rept. Progress, 1900, p. r 107. 



|| The Iroquois Beach, Trans. Canadian Institute, vol. vi, p. 29 et seq. 



