ANCIENT STRAIT AT NIPISSING. 623 



Nelson are built on it east of the road. It is a broad, composite beach ridge com- 

 posed of rounded gravel, rather fine, but with some pebbles and a few cobbles. To 

 the south it faces in a series of steps of five to six feet each over the McEwen beach 

 and the flat beyond, which drops at a distance of about two miles by a deep descent 

 to the bed of the ancient river channel. I learned by inquiry that this gravel 

 ridge extends westward through the lands of Messrs Elliott and Thomson and 

 probably eastward also for a considerable distance. 



The Nelson beach is in contour with a large swampy tract north of it. On the 

 Temiscamang road this swamp is about a mile wide, but with two or three insular 

 patches of higher ground in it. On the front of the former mainland on the north 

 side of this swamp I found a small amount of washed, rounded gravel, but it only 

 reached up to five or six feet, which is no higher than the top of the Nelson ridge. 



The rxsuBMERGED Area. 



This concludes the sum of the positive evidences observed on the hills north of 

 North bay. Toward the north the country is rough, the clearings in the forest are 

 few, and there are many swampy, almost impassable places ; but my investigations 

 did not stop at the Nelson beach. The process of making a reliable determination 

 of the upper limit of postglacial submergence requires the gathering of negative 

 evidences from the higher ground as well as positive evidences from below. On 

 the first excursion on the Temiscamang road we drove north from Nelsons a mile 

 and a quarter to Hills corner, and from there east two miles and a quarter to the 

 farm of Mr Bailey, which is next south of Four Mile lake. Several gravel ridges 

 were seen, but I was unable to recognize the work of waves in any of them. I 

 am quite sure they were all glacial forms. Their positions and surroundings, as 

 well as their forms, were unlike true littoral features. About half a mile east of 

 Hills corner there is a small, short gravel ridge which juts eastward from a drift 

 mass somewhat after the fasliion of a wave-built spit. It is composed mainly of 

 good sized pebbles well rounded ; but it is in a protected place, and the adjacent 

 slopes at the same level, wliich are well cleared and easy to see, show no sign of 

 wave action whatever. Again, half a mile east of Carmichaels corner are more 

 fine gravel ridges. They appeared' to be in the midst of a swamp, are quite irregu- 

 lar in form, with spurs and hollows, and they rise steeply ten to fifteen feet. I 

 regard them as cliaracteristic glacial forms, and they are so delicate in their struct- 

 ure that they could hardly have escaped modification if the waves had ever touched 

 them. The ground along this road is most of it plentifully covered with bowlders 

 of good size, and they are set in drift composed mainly of clay. At Baile^v'S we 

 were about 110 feet above the Nelson Ijeach. By a rough estimate, without 

 measurement, I concluded that Four Mile lake is somewhat below the level at 

 Nelsons. Mr Bailey told me that his land was almost entirely free from bowlders. 

 South of the road it rises in a smooth hill of almost pure clay drift which Avould 

 be exposed towards the east and southeast if submerged to the level of the road. 



While these negative evidences seemed fairly conclusive, they were not entirely 

 so, for I heard of other large gravel ridges fiirthei* north on the Temiscamang road. 

 On the second excursion I went three miles north from Carmichaels corner and 

 half a mile east to the farm of :Mr Sache, close to the east side of Caribou lake. 

 One mile north of Carmichaels I found the gravel ridges referred to partly on the 

 land of Mr Lydiott. They are immense irregular ridges about 40 feet high and 



