138 A. p. COLEMAN MARINE AND FRESHWATER BEACHES 



Since the marine beds were formed sufficient time lias elapsed to allow 

 the region of Ottawa to rise 470 feet, and that of Montreal 560 or perhaps 

 615 feet, and within the same time limits apparently 6 species of ani- 

 mals have become extinct — 4 insects, an ostracode (Estheria dawsoni), and 

 a sponge {Craniella logani^ Daws.). 



In addition to the considerations just mentioned, the i)resent beach 

 of lake Ontario, with its fairl}^ mature forms, including the cutting of 

 cliffs hundreds of feet high and the building of gravel bars miles in 

 length, as at Scarboro and Toronto, must have been worked out since 

 the barrier at the Thousand islands came into existence, and therefore 

 since the completion of the marine deposits just to the east, for thes' 

 rise a hundred feet above it. 



Though we do not know the exact rate of an}' of these operations, all 

 of them seem to demand a large amount of time, and tlie lower limit, 

 of 2,500 3^ears, let us say since the time of Pericles or the founding of 

 Rome, seems quite inadequate, and even the upper one, of 16,000 years, 

 not too great. 



High-level Beaches in southern Ontario 



Two or three hundred feet above the most westerly deposits containing 

 marine fossils is the splendidl}' developed Iroquois beach, followed by 

 the Nipissing, Algonquin, and Warren shorelines, all very distinct and 

 fairl}' well known through the labors of Spencer, Gilbert, Taylor, and 

 others. These need not be discussed here, except to mention that a few 

 freshwater shells have been found in the Iroquois beach, and that great 

 numbers of freshwater fossils are found in an extensive area near Geor- 

 gian bay, probably belonging to lake Algonquin, though possibly to lake 

 Warren, showing that at least two of these higher beaclies are not marine. 



There are, however, beach deposits at higher levels than any of the old 

 shorelines mentioned, the highest of which, so far as recorded, reaches 

 1,230 feet above tlie sea.* On the highlands of the i)eninsula between 

 lake Huron and Georgian bay Doctor Spencer has found several frag- 

 ments of beaches, around what must have been an old island, at levels 

 from 1,400 to 1,690 feet,t and similar beaches have been described l)y the 

 present writer at points 1,422 to 1521 feet above the sea in the same dis- 

 trict.J: Some of these are well marked water-levels, with broad terraces 



* Mr Taylor mentions water-levels at l,'2iK) to 1,2:J0 feet near Trout creek, Cartier, etcetera, prob- 

 abh' belonging to the Algonquin shores. Am. Geo!., vol. xiv, 1894, p. 28i>. He describes also 

 beaches at 1,.")H0 or IjMO feet west of Port Arthur, belonging, however, to a relatively small ice- 

 dammed lake which he has named lake Kaministiquia. 



f History of the Great Lakes, p. 78. 



X Bur. Mines Out., I'KiO, pp. 17(i, 177. 



