NATURAL HISTORY AND PHYSIOGRAPHY OF NEW BRUNSWICK. 
4o9 
river changes again, and, especially at the twenty and one-half mile bend, 
it assumes the gentle slope and drift-bottomed character of an old 
valley. This matured character becomes yet better marked below the 
twenty-one and one-half mile bend. At the twenty and one-half mile 
bend there appears to be an old valley entering the main river in the 
line of the stretch between twenty and one-half and twenty-one miles, 
and this, I believe, was the pre-Glacial mouth of Libby’s Brook. If 
now, the pre-Glacial channel ran as shown on the map, the part of the 
valley from the twenty and one-half mile bend to the twenty-one and 
one-half mile bend must have been in pre-Glacial times a part of labbys 
Brook. At these falls the ancient peneplain character of the country 
is very marked. The line between plain and river valley (viz., the rim 
of the valley) is sharp and level. By actual aneroid measurement this 
plain here lies about 250 feet above the river, and hence 800 feet above 
the sea. 
From the twenty-one and one-half mile bend to the Lower North 
Branch the river is pleasant and more open, with a steady slope, but 
no bad rapids nor falls. Just above the Lower North Branch is a 
small rocky rapid, evidently post-Glacial, and the pre-Glacial valley is 
beautifully clear on the north bank. The Lower North Branch 
enters with rocky falls, also evidently post-Glacial, and the original 
survey map by Berton has on this branch this legend, “ very rocky and 
broken for three miles up.” At the twenty-five and one-half mile bend, 
however, a broad, low valley extends northwestward, and no doubt 
represents the pre-Glacial mouth and lower course of the Lower North 
Branch. 
The scenery at the mouth of the Lower North Branch is altogether 
charming, as indeed it is at many points along this remarkable river. 
For a mile below the Lower North Branch the river is drift- 
bottomed, open, and of ancient aspect; but at the twenty-five and one- 
half mile bend it narrows somewhat, here passing, according to our 
geological maps, from the pre-Cambrian to the Cambro-Silurian forma- 
tion. Below twenty-six miles, begins another short series of falls over 
rocky ledges, extending to twenty-seven miles. These are also typic- 
ally post-Glacial, and both ends of the pre-Glacial valley are clearly 
visible on the North Bank. This is the lowest series of bad rapids on 
' the river. 
