﻿230 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Apr. 9, 



have comminuted masses of the sub-rock, equably mixed with erratic 

 blocks, — forming sand, clay, or gravel. 



In the chasm near the Falls I only saw one boulder ; this was 

 gneiss with garnets, — from the north, — precisely similar to what I 

 saw on Lake Nipissing. The fields for a mile or more (most proba- 

 bly much further) in the rear of the Canada side of this river present 

 numerous erratic blocks, — dropped at hazard, as it were. Many of 

 them are gneiss and syenite, but a large proportion are a peculiar 

 blue milky quartz-rock, which is found in situ in large quantity on 

 Law's Farm, three miles N.E. or N.N.E. of Kingston, on Lake On- 

 tario, 200 miles to the E.N.E. of the spot on which they now lie. 

 Others are Medina Sandstone, and angular masses of dark blue lime- 

 stone from the Humber (eight miles west of Toronto, due north of 

 the Niagara Falls), full of fossils, — Mytilus and Strophomena, cha- 

 racteristic of the Hudson group of sedimentary rocks. 



The same rolled milky quartz and Humber limestone prevail in 

 the debris lying in the fields on the west shore of Lake Ontario, both 

 above and below the high ridge, which forms the continuation of 

 Queenston Heights. 



Lakes Ontario and Simcoe. — Lake Ontario is 234 feet above the 

 sea, and 322 feet (330 feet, according to Mr. Logan) below Lake 

 Erie. Almost everything is yet to be ascertained respecting the 

 height and composition of the containing margin of Lake Ontario. 

 One or two points of elevation only on the north and south sides are 

 known with accuracy ; the rest are estimates. 



Two, three, or more lofty terraces or ridges, allowing a wide outlet 

 on the north-east, wander round the lake at various distances, usually 

 out of sight, but occasionally near. 



The highest at present known on the north shore, in the rear of 

 Toronto, is 680 feet above sea-level ; and the highest on the south 

 shore is 762 feet above the same base ; the former is the estimate of 

 Sir Charles Lyell, the latter according to the measurements of civil 

 engineers. 



With these few words premised, I shall proceed, as before, to ex- 

 tract from my own note-books. 



On travelling from Toronto to Holland's Landing on Lake Simcoe, 

 along Yonge Street, a distance of 37 miles, I found three boulders 

 (one weighing a ton) of the mixed petalite, soon to be spoken of, at 

 twelve and fourteen miles from Toronto. The fields between ten 

 and eighteen miles from Toronto are tolerably free from boulders ; 

 but for the next eleven miles (to the twenty-ninth mile from To- 

 ronto) the boulders become abundant, and are gneiss, quartz-rock, 

 syenite, coarse mica-slate, white marble, conglomerate of primitive 

 rocks, the smooth brown Matchedash Limestone from the north of 

 Lake Simcoe, and a limestone from the same vicinity, whose fossils 

 are arenaceous casts. 



From this point to Holland's Landing erratics become rare ; but 

 the eminences in the rear of the sandy flat upon which that hamlet is 

 built are crowned with many large boulders. Erratics similar in kind 

 to the foregoing also load the west side of the river all the way to 



