in some of our Post Tertiary Deposits, 47 



found. Many of the bivalves were perfect, having the valves 

 closed, and from the position in which they were found, appeared 

 to have lived on the spot where they are buried. These shells 

 may have lain here for thousands of years, although their geolo- 

 gical date is extremely recent. 



Similar terraces occur on Goat Island, and along the American 

 side of the river from the Falls to the whirlpool. A mastodon's 

 tooth was found in this ftuviatile terrace opposite Goat Island, at 

 a depth of nine feet below the surface, but it does not follow from 

 this, that the mastodon lived at the time of its formation, for the 

 tooth might have been washed from an older deposit. These 

 terraces being all on the same level, and the Uhiones occurring in 

 them in the position in which they had lived, are facts which im- 

 ply that they were once connected so as to form a continuous 

 stratum, extending over the position occupied by the present 

 gorge, and also that they have been deposited in a tranquil 

 widening of the river, like that between Chippawa and Buffalo. 

 They also afford a conclusive proof that the Falls have receded. 

 These terraces are described by Hall, Lyell and Ramsay. 



Terraces around Georgian Bay. 



The more inaccessible parts of the Province have naturally re- 

 ceived less of the attention of scientific men, than those in the 

 vicinity of her cities or along her great thoroughfares. I am not 

 aware of anything having yet been published in regard to the 

 lake terraces of the region under notice, with the exception of a 

 paper by Sandford Fleming, C. E., on '* The Valley of the Not- 

 tawasaga,"* from which I extract the following : — 



" There are appearances in various parts of this region which lead us 

 to infer that the waters of Lake Huron like those of Ontario, formerly 

 stood at higher levels than they at present occupy. Parallel terraces 

 and ridges of sand and gravel can be traced at different places winding 

 round the heads of bays and points of high land with perfect horizon- 

 tatlity, and resembling in every respect the present lake beaches ; one of 

 them particularly strikes the attention in the Bay of Penetanguishene, 

 at a height of about 70 feet above the level of the lake ; it can be seen dis- 

 tinctly on either side from the water, or by a spectator standing on one 

 bank while the sun shines obliquely on the other, so as to throw the 

 deeper parts of the terrace in shadow. The accompanying section, 

 sketched! from a cutting a little below Jeffrey's tavern, in the Village of 



* Read before the Canadian Institute in 1853, and published in the 

 first volume of the Canadian Journal. 



t This sketch resembles a cross section of a side-hill road, where the 

 earth has been excavated on the upper and thrown to the lower side. 



