In this paper, Mr. Tyrrell makes the following comprehensive reference to the physical geography of this extensive region:—He says:—“In general character the country is a vast undulating plain, underlain by a stony clay, and covered with a short grass or deciduous Arctic plants. In certain sections no rising ground can be seen for miles around, and in other sections rocky hills rise through the general covering of clay. The whole land reminds one forcibly of the great plains of Western Canada, the chief points of difference being caused by the differences in the underlying rocky-floor. The boulder-clay underlying the plains is deposited on a floor of soft Cretaceous shales and sandstones, and even where the soft rocks crop out at the surface they rarely form conspicuous hills; the boulder-clay underlying the Barren Lands is deposited largely on a floor of igneous, or hard, highly altered rocks, which, wherever they appear at the surface, form rocky knolls that stand up distinctly above the surrounding clay, while the boulder-clay itself, being formed out of material derived from the hard granitoid rocks, is much more stony than the clay of the more southern plains.
No High Altitudes.
“No part of the country rises to any great altitude above the sea, the highest point being probably the ridge of rocky hills called Stony mountains, which run along the east side of Coppermine river, and are said to rise about fifteen hundred feet above the sea. Ennadai lake lies eleven hundred feet above the sea, Dubawnt[[24]] lies five hundred feet, and the Yathkyed lake three hundred feet.
“The country may conveniently be divided into two distinct portions, namely, the Interior Upland and the Coastal Plain.
“The Interior Upland includes all those parts of the country lying above the highest ancient shore-line, either of Hudson bay or of Arctic ocean, and has a mean elevation of from nine hundred to one thousand feet above the sea. Its surface is composed largely of sandy boulder-clay, and rounded boulders or broken fragments of the underlying rock. Low ridges and rugged, irregular hills are common over the surface, while eskers, or long straight ridges of sand or gravel, extend in uninterrupted courses over hills and valleys alike. Here and there some ancient beaches mark the positions of small lakes which have long since disappeared.
The Coastal Plain.
“The Coastal Plain lies between the highest ancient post-glacial seabeach and the present seashore, sloping gradually from a height of five hundred to six hundred feet down to the sea-level. Much of this plain has a stony surface, like that of the Interior Upland, but it is diversified with sandy plains, and on all the steeper slopes gravel terraces or coast cliffs mark the lines of the old seashore. Many of the terraces fill narrow gaps between adjoining hills, and the lower ones are often strewn with shells such as are found in Hudson bay at the present time. The waves have reduced the surface irregularities of this portion of the country to some extent, but the more rocky districts, such as those in the vicinity of Chesterfield inlet are still, except for the presence of the little terraces, as rough and rugged as before they were covered by the sea, and the highest parts are probably barer, for any loose material that had been left on them by the ice-sheet of the glacial period has been washed by the waves into the depressions. The breadth of the plain in the vicinity of Churchill is about fifty miles. Farther north it becomes broader, until, in the latitude of Yathkyed lake, it has a breadth of one hundred and twenty-five miles, and at the north end of Dubawnt lake extends westward for three hundred miles. North of Dubawnt river its extent is not yet known, but many of the old sand plains and terraces reported from the banks of Backs river probably mark old shore-lines on this Coastal Plain, there sloping northward toward Arctic ocean.
“In a few places the coast-line is fairly high but as a rule it is low, and slopes gently down into a shallow sea. The whole country has a fairly general slope northeastward, and the three principal streams which drain it have a more or less parallel course in that direction, while other smaller streams flow more directly towards the coast, northward to Arctic ocean and eastward to Hudson bay.
The Three Principal Rivers.
“These three streams are Thlew-e-cho, Great Fish or Backs river, Telzoa or Dubawnt river and Kazan river.