1908.] PHYSICAL GEOGRAPHY ATHABASKA VALLEY. 19 



and lakes, of which Lesser Slave. TO miles in length, is by far the 

 largest, occupy its shallow valleys. Immense areas have been swept 

 by fire (fig. 2), sometimes repeatedly, and in places the original forest 

 covering has been destroyed and small prairies have succeeded. 



The country lying between the Athabaska and Peace rivers, and 

 drained in part by the latter stream, may be best characterized by 

 quoting in part the account by McConnell, who examined it in the 

 summer of 1889: 



The country between the Peace and Athabasca rivers north of Lesser Slave 

 Lake, comprising an area of about 44,<>im) square miles, * * * may be 

 described as a gently undulating wooded plain, diversified with numerous shallow- 

 lakes, muskegs and marshes. Small prairie patches, manifestly due to forest 

 Fires, occur north of the west end of Lesser Slave Lake, at several points along 

 the Loon and Wabiscaw rivers, * * * but their total area is relatively 

 insignificant. 



The rolling plains between Peace River and the Athabasca are relieved by 

 several high ridges or plateaus, all of which owe their origin to a differential 

 denudation of the soft rocks on which the plains are based. Of these Marten 

 Mountain is situated north-east of Lesser Slave Lake, above which it rises to 

 the height of about 1,000 feet. The Buffalo Head Hills commence abruptly 

 about fifty miles above the mouth of the Loon Liver, with an elevation of 

 about L'.r>()0 feet above the Sea, and running in a south-south-westerly direc- 

 tion die away opposite the month of Battle Liver, while Birch Mountain ex- 

 tends for nearly ninety miles along the lower part of the Athabasca, from which 

 it is separated by a plain fifteen to twenty miles wide. Among the smaller 

 elevations are Trout Mountain, which is situated north of the Wabiscaw Liver, 

 and the Thickwood Hills, winch lie south of Birch Mountain. The uplands of 

 the district, like the lowlands, are all wooded, and are dotted everywhere with 

 lakes and marshes. 



The climatic conditions of the various parts of Athabaska Valley 

 vary considerably, according to location. The more open portions 

 of the upper part of the valley, though lying at a considerable alti- 

 tude, enjoy the ' chinook ' winds, which so temper the climate that 

 it compares favorably with more easterly regions lying much farther 

 south. Lack of detailed data precludes the possibility of comparing 

 absolutely the climatic conditions of the upper and lower Athabaska, 

 but the effects of the ' chinook ' winds are felt to some extent through- 

 out the course of the river. 



The following table will give a good idea of the climatic conditions 

 at Athabaska Landing:'' 



"Ann. Rept. Geol. Snrv. Canada, Y (new ser.), pp. CD, 7I>. 1893. 



6 The tables of temperatures given in this report, unless otherwise noted, 

 are compiled from the Report of the Meteorological Service of Canada for the 

 year 1900. This seems to have been about an average year. ami. by using tem- 

 peratures taken simultaneously over the whole country, the figures for the 

 different sections are more strictly comparable than they would be if repre- 

 senting different years. All records are in degrees Fahrenheit. 



