igol] Ells — Ancient Channels. 25 



Culbute fall is much broader and rocks rarely appear along its 

 course except at the crossing- of the road north from Chapais. 

 Below this the shores are of clay or sand till the end of the Island 

 is reached where the Pembroke channel joins the Culbute, flowing- 

 over broad ledges of Black River limestone, and forming what is 

 known as the Paquette Rapid which is about a fourth of a mile 

 south of the junction of the two channels. 



The Pembroke channel which flows past the south side of 

 Allumette Island is not deep. At the upper end rapids extend 

 partly across the river and there are many small granite islets. 

 Along- the south shore of the river especially above the mouth of 

 the Petewawa the banks are entirely of sand and in some places 

 are from fifty to eighty feet high. 



At the town of Pembroke a depression comes to the river 

 from the south and the Musquash River here joins the Ottawa. 

 This stream flows north-west against the regular course of 

 the Ottawa and discharges the Musquash and Mud Lakes, the 

 former of which is about ten miles in length. The stream is for 

 the most part sluggish, flowing through a clay flat for some miles. 

 On the north side of Musquash Lake a ridge of crystalline rocks 

 rises abruptly, and on the south side Palaeozoic rocks, mostly of 

 of Black River age, form outliers, which have steep scarped 

 sides towards the north as if cut down by the agency of running 

 water. 



At the upper end of Musquash Lake a stream flows in 

 which discharges a chain of long and narrow lakes, and these 

 continue for some miles in a depression into the township of Horton. 

 Along these lakes, which are surrounded by great masses of sand 

 the action of water is very evident. Some of them are long and 

 very narrow but have a depth of over a hundred feet, though only 

 a tew chains in width. They present all the features of an old 

 river channel which has been blocked up by great deposits of sand, 

 gravel and boulders, so that the original channel is now defined 

 simply by the line of the depression and the remnants of the old 

 river left in the narrow series of lakes. 



This depression extends out to the river again, reaching it 

 near what is known as the Chenaux rapids, about four miles below 

 the junction of the two channels which surround Calumet Island, 



