10 NORTH AMERICAN FAUNA. [no 19. 



rolling and consists entirol}'^ of granite rock, alxnit wliicli cling many 

 mosses and heathers, while small alpine junipers and hemlocks 

 struggle for existence in favorable places. The breeding birds found 

 with these Hudsonian plants were ptarmigan {Lagojim riqjestris and 

 L. leucuru-s)^ pipits {Anthus 2)e'H8ilva7iicus)^ rosy finches {Leucosticte t. 

 littoraUs)^ and golden -crowned sparrows {Zonotrichiacoronata). Char- 

 acteristic manmials noted were pikas {Oehotona collctris)^ hoary mar- 

 mots {Arctomys caUgatus)^ and mountain goats {Oreamnos m.ontmnis). 



Canadian Yukon district. — Lake subdivision: On the north side of 

 the divide the hemlocks are soon replaced by pines and spruces, and 

 in the vicinity of Shallow Lake the boundary of the interior fauna and 

 flora is reached. The change is complete at Log Cabin, British Colum- 

 bia, nine miles from the head of Lake Bennett, where the characteristic 

 features of the Canadian zone are again established and the general 

 aspect of the country is very different. The most abundant tree is the 

 white spruce {Picea canadensis)^ and among shrubs seen for the first 

 time the buffalo berry {LepciTgyrmi canadensis) is very common. 

 Birds marking a change of fauna are the slate-colored junco {Jwico 

 hyeinalis)., the Alaska jay {Perisoreus canadensis fumifi'ons)., the inter- 

 mediate sparrow [Zonotrichia I. gamheli)., and the l)lack-poll warbler 

 {Devdroica st7'iata). A new chipmunk {Entamias caniceps) is very 

 conspicuous. At the head of Lake Bennett another change occurs; 

 the country becomes more arid and rocky and there is a tinge of 

 Hudsonian. 



Lake Bennett is a long, narrow sheet of water inclosed by high 

 granite clifl's, the sides of which are often so steep as to l)e unfavorable 

 for plant and animal life, and whose summits are doubtless similar to 

 White Pass in fauna and flora. Cold winds sweep down the lake much 

 of the time, and cool shadows envelop the east side most of the fore- 

 noon and the west side most of the afternoon, so that opportunity for 

 warmth by direct sunlight is limited. Hence there is quite a strong 

 Hudsonian element about the lake. Among the plants^ collected here 

 are the pale dwarf laurel {Kalmia glauca)^ the Greek valerian 

 {Polemmiitim Immile)^ the forget-me-not {Myosotls sylvatica alpestrL-i), 

 the alpine juniper {Juniperus )uma), the bush cranberry {Vihurmim 

 pauciflormii).^ the dwarf birch {Betula glandidosd)^ the bearberry 

 {Arctostaphylos uvaursi)^ the buffalo berry {Lepargyrwa canadensis), 

 the shadbush {Amekmchie?' alnifolia), the Labrador tea (Ledum grcen- 

 Jandicuiiii), and the black crowberiy {Enijxti'um nigrum). Where 

 trickling streams come down to the lake alder thickets abound, and 

 along terraces of rock clumps of pines and spruces as well as poplars 

 find suppoit. Among Hudsonian mammals were found pikas {Oeho- 

 tona collar is), hoary marmots {Arctoviys caligatus), and Dall sheep 



'Identified by F. V. Coville, chief botanist, U. S. Department of Agriculture. 



