Postglacial Submergence east of Georgian bay. — Taylor. 279 
extend in a great curve around to the north and join the sec- 
ond. From the first ridge the long level of the terrace extend- 
ing for two or three miles to the north is plainly seen. 
Returning to the lower ground, we found that the sandy 
plain which forms the banks of the river at Bracebridge is the 
top of a great deposit of silt and clay, and that the town itself 
is situated upon an eroded slope of this great bed. Several 
excavations in the streets showed its character very well. The 
banks along the river are steep and, below the falls, 90 to 100 
feet high. In some places this whole depth is composed of 
the laminated beds. It is plain that the extent of this deposit 
was once considerably greater than now; for the numerous 
deep ravines which have been cut into jt since the recession of 
the water show how much has been removed. 
We drove also about seven miles southeast, past the falls of 
the south branch of the Muskoka river, to a point about two 
miles above. For the first mile the road is over the deeply 
gullied surface of the silt plain. Then the road passes over 
a hill, at an altitude of about 90 feet above the railroad sta- 
tion, and on the top of this hill are several well formed beach 
ridges of water-worn gravel with depressions between them. 
Beyond this the road descends through a very deep and steep- 
sided valley which has been cut out of the silt by a small 
stream. Both sides show the laminated fine sediments to a 
depth of over 100 feet. The beaches mentioned are on the top 
of the north bank, and the contact between them and the silt 
may be seen in the ditch by the roadside. Between this gully 
and South falls the road passes over some higher ground which 
is pretty heavily covered with dune sand, and is at about the 
same level as the sandy tract northeast of Bracebridge, but 
considerably below the highest beach. 
From Bracebridge to Muskoka lake, the Muskoka river is a 
navigable stream flowing with a sluggish current through a 
great expanse of swampy Hats. After the maximum sub- 
mergence, during which the upper part of the former estuary 
of the Muskoka was filled with the silts and cla} r s. the reces- 
sion of the waters was accompanied by ;i restored activity of 
the river, which then commenced the re-excavation of its bed. 
We have in consequence the level plain of the silts at Brace- 
bridge cut by the narrow, deep gorges of the river and of sev- 
