No. 2.] SPENCER — PREGLACIAL OUTLET OF L. ERIE. 79 



4. Lake Erie emptied by a buried channel a few miles west- 

 ward of the present mouth of the Grand River, and flowed for 

 half a dozen miles to near Cayuga, where it entered the present 

 valley, and continued this channel (reversed) to a place at a 

 short distance westward of Seneca, whence it turned into the 

 basin referred to above, receiving the upper waters of the Grand 

 River and Neith's Creek as tributaries, and then emptied into 

 Lake Ontario, by the Dundas valley. This channel was also 

 deep enough to drain Lake Huron. ■« 



5. Throucrhout nearly the whole lensTth of Lake Ontario, and 

 at no great distance from its southern shore, there is a submerged 

 escarpment (of the Hudson River Formation) which, in magni- 

 tude, is comparable with the Niagara escarpment itself, now 

 skirting the lake shore. It was along the foot of this escarpment 

 that the river from the Dundas valley flowed (giving it the present 

 form) to eastward of, or near to, Oswego, receiving many streams 

 along its course. 



5. The western portion of the Lake Erie basin, the south- 

 western counties of Ontario, and the southern portion of the 

 basin of Lake Huron formed one Preglacial plane, which is 

 now covered with drift or water (or with both) to a depth varying 

 from fifty to one hundred feet, excepting in channels where the 

 filling by drift is very great. A deep channel draining Lake 

 Huron extended through this region, leaving the present lake 

 near the Au Sable River, and entering the Erie basin between 

 Port Stanley and Vienna, at a depth near its known margin of 

 200 feet, but at a probable depth in the centre sufficiently great 

 to drain Lake Huron. 



6. The Preglacial valleys (now buried) of Ohio and Pennsyl- 

 vania — for example ; the Cuyahoga, Mahoning (reversed), and 

 Alleghany (deflected), formed tributaries to the great river flowing 

 through the Erie basin and the Dundas valley. 



7. The bays and inlets north of Lake Huron arertrue fiords 

 in character, and are of aqueous origin. 



8. The Great Lakes owe their existence to sub-aerial and 

 fluviatile agencies, being old valleys of erosion of great age, but 

 with their outlets closed by drift. Glaciers did not excavate the 

 lakes and had no important action in bringing about the present 

 topography of the basins. 



9. The old outlet of the Niagara river, by the valley of St. 

 David's, was probably an interglacial channel. 



