212 BR. W. ELLS—SANDS AND CLAYS OF THE OTTAWA BASIN. 
siderable differences in the products of decomposition resulting from 
the several agencies to which they have been exposed. 
PHystcAL FEATURES OF THE Orrawa Bastin 
PREVIOUS INVESTIGATIONS AND THEIR RESULTS 
In the “ Geology of Canada” * the distribution and origin of the sands 
and clays of the lower Ottawa and Saint Lawrence basins were very fully 
discussed, in so far as the explorations of that district had then been 
prosecuted. The area along the lower Ottawa there described was com- 
prised chiefly in the generally level portion between the Rideau and the 
Saint Lawrence, as but few attempts had at that time been made to pen- 
etrate the wilderness country to the north and west. Within the last 
twenty years, however, most of the large streams which traverse the 
country to the north and south of the Ottawa have been examined, and 
in many cases these have been followed to their sources; and in this 
way a large amount of interesting and valuable information regarding 
the physical features of these comparatively remote and hitherto un- 
known regions has been collected by the several observers in this area, 
and many new facts of interest relating to the great questions of glacial 
and postglacial geology have been obtained. 
THE UPPER OTTAWA 
The peculiar course of the Ottawa in its upper portion, to the north of 
lake Temiscaming, forms, by its doubling on itself in its lower or east- 
ward stretch, a loop-shaped area, extending eastward from that lake to 
the Gatineau, one of the principal tributaries from the north, which enters 
the Ottawa river near the city of Ottawa. In this loop are included 
several large streams or branches, some of which extend almost entirely 
across the area. Among these are the Kippewa, the Black, the Dumoine, 
and the Coulonge, all of which have large tributaries and drainage basins. 
Some of these streams have apparently exercised an influence in deter- 
mining the present channel of the Ottawa, in connection with which a 
number of old and now partly filled channels can be easily recognized 
at different points between the outlet of lake Temiscaming and the Saint 
Lawrence river. 
HEIGHT-OF-LAND, LAKES AND RIVERS 
The height-of-land which divides the waters of the Ottawa basin from 
those which flow into James bay on the one hand, or into the lower Saint 
Lawrence on the other, is found a short distance to the north of the upper 
or westward course of the stream. 
* Geology of Canada, 1863, pp. 916-920, 
