OCT., 1900.] FAUNAL DISTRICTS. 13 



the Bennett grouiul s(|uiiTel {Speriiwpldlwi em^et'rai}le><lui<)^ the North- 

 ern bushj'-tailed rat {^W'otoiiia saxamans)^ white-footed mice {Peramys- 

 Gus oreas and Peroiiiyscas riianicuIatHS arcticm), and the varying hare 

 {Zepus S(d!em). All of these species and three of the genera, FAitmnias^ 

 Neotoma^ and Peromyscus^ find their northern limits in this district. 

 Among birds that are known from the Yukon only in this district may 

 be mentioned the sparrow hawk {Faico sjHirrerlm), the screech owl 

 {Megascops ado I'oinicottif)^ the night hawk ( CJwrdeiles virginlanus)^ 

 the tree swallow {Tachycineta hicoJor)^ the Tennessee warbler {Ilehnin- 

 t}ioph'dit2>ere(jrin(i)^ the pileolated warl:»ler ( Wdsonla jyiiAiilla plleolatcib)^ 

 and the mountain bluebird {Slalia arctica). Of these, CJwrdeiles is 

 perhaps the most noteworthy, as it is decidedly a southern genus. It 

 is very common, and was seen nightly from Caribou Crossing to Rink 

 Rapids, but after we had passed that point it disappeared. Its range 

 in this region as observed by us is probably accurate and corresponds 

 with the limits of the district. Among trees, the lodgepole pine 

 {Pinus 7mMrrayana) is common throughout the district, but does not 

 extend beyond it. 



Iludsoniojii Yidion district. — This district, as here considered, 

 includes till of the Yukon region from Fort Selkirk to the limit of 

 trees. The Lewes River is joined at Fort Selkirk by the Pelly, after 

 which the increased volume of water flows on between heavily forested 

 slopes and jutting cliffs (Plate III, fig. 2), which replace the sandy 

 banks of the upper river. From the mouth of the Selw}^! northward 

 the topography of the river banks is but slightly different. The num- 

 ber of poplars in the forest is much increased; the spruces are corre- 

 spondingly decreased not only in number but also in size; while the 

 birches about hold their own, and the pines are not present at all, 

 having disappeared between Fort Selkirk and the mouth of the Sehv3^n 

 River. As we approach Dawson spruces become dwarfed and entirely 

 subordinate to the poplars, which crowd their l)ushy tops together for 

 miles and miles. The spruces are in the gulches and in small clumps 

 elsewhere, and a few are scattered about, their dark-green spike tops 

 showing off well against the billowy mass of the lighter foliage of 

 poplar and birch. The undergrowth remains much the same, and 

 deep moss covers the ground and rocks. In damp sandy places along 

 shore and on islands occasionally overflowed a bright-green scouring 

 rush {E(pdsetum) grows so abundantly as to be a characteristic plant. 

 The alpine juniper {Juniperus nana) is found occasionally on hill- 

 sides not too thickly grown with poplars, and on the more open hill- 

 sides the landscape is brightened liy masses of fireweed ( ChamcBnerion 

 angusti folium), for even here forest fires are not a novelty. 



Two more large rivers, the White and the Stewart, empty into the 

 Yukon in this vicinity. About the mouths of these and other tributaries 

 is more or less low country covered with willows. Islands become 



