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NATURALIST'S GUIDE TO THE AMERICAS 



are the Athabaska Landing branch of the 

 Canadian Northern, running 100 mi. 

 northward from Edmonton, and the E. 

 D. and B. C. railway running to Peace 

 River by way of Lesser Slave Lake. 

 The latter line affords access to the 

 Mackenzie by way of the lower Peace 

 and Slave River, or to the upper tribu- 

 taries of Peace River, in the interior of 

 northern British Columbia. Another 

 route to the latter section is by canoe 

 northward from various points on the 

 Canadian National railway, which 

 crosses central British Columbia from 

 the head of Fraser River to the Pacific 

 in about latitude 54. 



2. Climate of entire region 



The climate of a region of such magni- 

 tude as the one under discussion is so 

 varied that it seems best to take up this 

 subject in the account of the various 

 areas. In general it may be said that 

 the winters are long and cold, and the 

 summers short and comparatively warm. 

 There is a very wide yearly range of 

 temperature especially over the Conti- 

 nental portion of the region, the greatly 

 increased number of hours of sunlight 

 enjoyed in summers in high latitudes 

 making up in a measure for the increase 

 in latitude. This enables the smaller 

 shrubs and other plants to complete 

 their reproductive processes within a 

 comparatively short time. 



8. Original biotic divisions 



A. Poplar forest and savanna of south- 

 ern portion (Canadian Zone). This 

 division occupies most of a broad strip 

 extending north-northwestward from 

 Edmonton, passing west of Athabaska 

 (on the river), thence, including the 

 basin of Lesser Slave Lake, on to Peace 

 River, northward down its valley on 

 either side, and northward nearly to 

 Great Slave Lake. In a modified form, 

 it stretches westward to include much 

 of the Peace River valley, in northeast- 

 ern British Columbia. 



This is the region of transition from 

 the grassy and treeless Great Plains to 



the great northern Forest. Its principal 

 tree is the aspen poplar (Populus tremu- 

 loides) which forms groves of greater 

 or lesser extent on the slopes of the rol- 

 ling hills. In low areas where the 

 drainage is imperfect, mossy swamps or 

 muskegs where the black spruce (Picea 

 mariana} is dominant are frequent. 

 Farther north these become more 

 numerous and become a dominant 

 feature. 



Originally this area was the habitat 

 of the bison (Bison b. athabascae) and 

 the elk (Cervus canadensis), but the 

 latter is long since extirpated here, and 

 the bison remains only in small numbers 

 near its northern part. Other mammals 

 presumably here were the moose (Alces 

 americanus), Franklin ground squirrel 

 (Citellus franklinii), thirteen-lined 

 ground-squirrel (C. tridecemlineatus) 

 (these two not north of Athabaska 

 River), Saskatchewan pocket-gopher 

 (Thomomys talpoides) (southerly), nor- 

 thern plains skunk (Mephitis hudsonica), 

 and several mice and voles. Birds are 

 numerous; a few notable breeders in- 

 clude the sharp-tailed grouse, upland 

 plover, and the western solitary sand- 

 piper. 



The only reptile, the northern garter 

 snake (Thamnophis sirtalis parietalis), 

 which enters any part of the region is 

 confined mainly to the savannas of this 

 subdivision. Scarcely less strictly con- 

 fined to it are the western toad (Bufo 

 lentiginosus woodhousei), and the leopard 

 frog (Rana pipiens). The northern 

 wood frog (Rana cantabrigensis latire- 

 mis) and the northern chorophilus (Cho- 

 rophilus septentrionalis) also are found 

 in it, but extend their ranges far be- 

 yond to the limit of trees. 



B. Transcontinental coniferous area. 

 1. Southern heavy timber (Canadian 

 Zone): Covering most of the region 

 under discussion is the great transcon- 

 tinental conifer forest. Its principal 

 trees are the white and black spruces 

 (Picea alba and P. mariana), whose 

 ranges are coextensive with its limits, 

 and the canoe birch (Betula papyrifera), 

 tamarack (Larix laricina), aspen and 



