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NATURALIST'S GUIDE TO THE AMERICAS 



ately swift current and are usually 

 muddy, especially in spring and at times 

 of high water, when the clay banks are 

 cut down by the flood. Their courses 

 are characterized by a series of long 

 alternating curves, with cut banks on 

 the concave sides, and gravel bars 

 opposite. Spruce trees usually line 

 the high banks, and willows, alders and 

 poplars the lower younger shores. 

 Many islands usually wooded, occur. 



2. Lakes are numerous especially in 

 the area of primitive rocks, and are of 

 course bordered by rocky and sandy 

 shores, and contain many islands. 

 The principal ones form a more or less 

 connected system, part of a series 

 extending from Lake Superior to the 

 Arctic Sea. These lie along the junction 

 of the primitive or granitic and the 

 newer limestone formations, usually 

 heading in the primitive belt and out- 

 letting in the limestone district. They 

 are of irregular shape, usually sending 

 long arms eastward into the primitive 

 formation and north and south along 

 the junction of the two systems, though 

 in some cases the southern arms have 

 been filled by the sediment-bearing 

 streams which enter them. In addition 

 to the large lakes thousands of smaller 

 ones are scattered over the entire region. 



3. Marshes are numerous and in 

 several cases very extensive. The more 

 important of these will receive detailed 

 attention in the proper places. 



4. Fire-swept areas are all too com- 

 mon. In the case of coniferous woods, 

 a growth of deciduous woods usually 

 succeeds. 



II. PRESENT BIOTA 



Apart from the general reduction in 

 numbers of the game and fur bearing 

 animals, and the game birds, due to 

 partial settlement, the changes in the 

 fauna of the wooded parts of the region 

 are mainly chargeable to fire, which has 

 profoundly changed large areas. Some 

 sections have been reburned, sometimes 

 repeatedly, and in such the forest cover- 

 ing may be entirely destroyed, and 

 grassy prairie may succeed. Coniferous 



areas which are burned usually change 

 to the deciduous type, and this change 

 in type of forest is of course accompanied 

 by the ingression of certain birds and 

 mammals which were originally absent. 

 The most conspicuous mammalian ex- 

 amples are the mule deer (Odocoileus 

 hemionus}, which, within the past 

 century, has extended its range north- 

 ward for several hundred miles. The 

 coyote also (Cam's latrans), aided per- 

 haps by partial settlement within its 

 former habitat, has effected an extension 

 of its range even more notable. Among 

 birds, it is certain that the rose-breasted 

 grosbeak (Hedymeles ludoviciana) , has 

 traveled northwestward upwards of 500 

 mi., and there is reason to suspect that 

 several other species of small birds 

 have entered the region of the lower 

 Athabaska within historic times. This 

 ingression, probably caused in part at 

 least, by the changes referred to, has 

 not been accompanied by the loss of 

 any species excepting the elk (Cervus 

 canadensis), although many mammals, 

 notably the larger game animals and 

 especially the fur-bearers, have suffered 

 great reduction in numbers, and two 

 others, the northern bison (Bison b. 

 athabascae} , and the musk-ox (Ovibos 

 moschatus}, have had their ranges 

 greatly reduced. These reductions and 

 losses, however, it should be emphasized, 

 can not be charged to changes in the 

 character of the forest cover, but are 

 rather in line with the usual reduction 

 of the large animals which follow partial 

 settlement and the exploitation of the 

 natural resources of a region. 



Along the Arctic coast of Alaska and 

 Canada, the presence of whaling and 

 trading ships has resulted in great 

 diminution of the game animals. Since 

 about 1896, when the whalers begun to 

 winter at Herschel Island and Baillie 

 Island, and a few years later at Langton 

 Bay and in Coronation Gulf, the effect 

 has been serious. These vessels depend 

 largely on the game resources of the 

 country for subsistence, hiring the 

 natives as hunters. This has resulted 

 in the practical extermination of the 



