104 ROYAL SOCIETY OF CANADA 
Below this, near the town of Pembroke, another old channel of the 
Ottawa evidently extended eastward through the depression in which the 
Muskrat river and lake are now situated. The continuation eastward 
of this old river bed is seen in a series of narrow but very deep lakes © 
which extend to the south of the present river at Portage du Fort and 
probably reached the Ottawa about four miles east of that point near 
the Chenaux rapids. 
Further east near the village of Fitzroy Harbour, another old 
channel evidently followed the course of the Carp river through the 
township of Huntley in the direction of Ottawa city; and mpre re- 
cently a series of borings to tlre south and east of Ottawa, in the direc- 
tion of Bear Brook and the South Nation river, shows the presence 
of a deep depression which is possibly the continuation of that just 
noted. This extended past Caledonia Springs and presumably came out 
to the present river course near the village of L’Orignal. 
This recent series of borings in the area to the south of the lower 
Ottawa furnishes a large amount of interesting information regarding 
the amount of denudation in the neighbourhood of the Ottawa river. 
One of the deepest yet recorded is on the bank of the South Nation 
river in the township of Plantagenet, and is reported to have reached 
a depth of 180 feet in clay. At this place the river has an elevation of 
not more than twenty feet above its junction with the Ottawa, which at 
this point is only 133 feet above mean tide at Quebec. The bottom 
of this old channel would appear therefore, to be nearly fifty feet below 
sea level, and the depth of the old valley is about 160 feet below the 
present surface of the Ottawa river. 
Nearly fifty bore-holes have been reported from this area south of 
the river, all of which are sunk in drift, and generally through blue clay. 
In some of these, deposits of quicksand were encountered, and in a 
number of them a layer of sand and gravel from one to five feet thick 
was found resting upon the underlying rock. The series of holes ex- 
tended from a short distance east of Ottawa city to the village of Cale- 
donia Springs, in the direction of Eastman’s Springs, Bear Brook, 
Pendleton and the present line of the South Nation river, west of the 
Ox Bow; but slight attempt was made to penetrate the underlying rock 
strata. In addition a number of holes were put down nearer the Ottawa 
itself and revealed the presence in that direction also of great thick- — 
nesses of clay at various points. ; 
When applied to the map of the area these borings show that a well. 
defined deep channel, now largely filled in with clay, sand and some-… 
times gravel, extended from the vicinity of Ottawa city in a generally } 
east course for nearly sixty miles. Its distance south of the present, 

