424 PROCEEDINGS OF OTTAWA MEETING. 



North bay, Ontario, is but little more than LOO feet, Lake Nipissing being, as we 

 make it, but (SI feet higher than Lake Huron, 66 feel above Jjsike Erie (water works, 

 south margin of North bay), and Trout lake, at the head of the Mattawa river, 

 but l'Dj feet above Lake Nipissing, while the col between is nowhere more than 

 about 25 feet above Trout lake A differential depression, therefore, of 1~>'» feet, 

 as between North bay and Niagara, would now divert the waters of the lakes by 

 the < Htawa river, while the passes between the Mattawa and Lake < mtario are all 

 of a considerably greater height. From these fads it was natural to expect that 



such an Outlet existed. 



We did not have time to trace the whole line of the supposed outlet, but the 

 following observations upon the local facts seemed to be sufficient to add greatly to 

 our confidence in Mr Gilbert's theory, if they do not, indeed, positively prove it. 

 The col between Lake Nipissing and Trout lake, extending from one lake to 

 another, a distance of two or three miles, is wholly occupied by a level swampy 

 tract, as already said, not more than 25 feet above Trout lake and unobstructed by 

 any continuous ridge of rocks or higher land. On the north this swamp is bordered 

 by an extension of an old beach-line of Lake Nipissing, constituting a clearly 

 defined terrace carrying a great abundance of well-rounded pebbles and extending 

 from lake to lake at a height of about 50 feet above the swamp referred to. This 

 beach borders the more elevated region which rises to the north. Upon the south 

 side of the passage between the two valleys the indentations are so extensive and 

 irregular that we did not have time to trace the corresponding shore line, but this 

 •would seem sufficient to show that the water of the lakes for sometime stood 

 between Lake Nipissing and Trout lake at such a relative level that if the way 

 down the Mattawa and Ottawa were free from obstruction it must have poured in 

 that' direction in torrential volume. If such a torrent poured down the Mattawa 

 the effects should show themselves in a pronounced manner in a bowlder terrace 

 at the junction of the Mattawa and Ottawa rivers, which is about 40 miles distant 

 (40 by railroad), and according to the railroad survey 95 feet lower in level, which 

 is about 80 above the river, making the difference of water levels (that is between 

 the top of the Nipissing-Trout lake terrace and low water at Mattawa) of about 

 225 feet (95 -f 50 -.- 80). 



Upon going down to the mouth of the Mattawa river we found an enormous 

 bowlder terrace far exceeding our expectations, which it would seem difficult to 

 account for on any other theory than that of the temporary existence at the close 

 of the Glacial Period of Gilbert's supposed torrential current of water from the 

 Great lakes. The bowldery delta terrace begins on the south side of the Mattawa 

 about three-quarters of a mile above the junction of the rivers and extends a some- 

 what less distance down the right bank of the Ottawa. It enlarges about the 

 middle of this distance and pushes out as a bar almost entirely across the < Utawa 

 river, making deep slack water above and turbulent rapids for a long distance 

 below. The terrace in this lower angle over the space mentioned < onsists entirely 

 of bowlders and well-rounded pebbles, which completely cover the surface and 

 apparently form the whole body of the terrace. The bowlders range in size from 



a few inches up to 30 feet iu diameter, and the terrace is level-topped, the height 

 above the river being, according to our estimate, about Ml feet. A short distance 

 back from the Ottawa riser there is a well-marked river channel cutting across that 

 portion of the deposit which projects as a bar into the Ottawa river. This is the 

 line of the flow of the .Mattawa river when it joined the ( Mlawa about a mile below 



