154 University of California Publications in Zoology [Vol. 24 



occur in fair abundance, and of others but an unsatisfactory repre- 

 sentation was obtained. 



As faunal areas, the Sitkan district and the country east of the 

 mountains are strongly contrasted. Differences of humidity are as 

 striking as those of temperature, and these differences are reflected in 

 the mammal, bird, and plant life of the two regions. The peculiarities 

 of the Sitkan district are well known, and the accepted boundaries well 

 defined. Of the country east of the mountains, as typified in the 

 Telegraph Creek region, the peculiarities are equally well marked. 

 This district, of undetermined extent, save where it impinges upon the 

 Sitkan district, appears worthy of a name as a recognizable faunal 

 area, for the sake of convenient reference, at least, and I would sug- 

 gest the adoption of Cassiar district, a name applied to it as a political 

 division. 



The birds of the two regions are more widely different than are the 

 mammals, that is, there are more distinct types in each region. The 

 two mammal faunas are distinct enough, and there are certain con- 

 spicuous species in each district that are not found in the other, but 

 in many cases closely related species or subspecies replace one another 

 on either side of the dividing line. Certain species of which a large 

 representation was obtained {Peromyscus and Microtus) exhibit inter- 

 gradation between related forms along the river to an extent far be- 

 yond anything found among the birds. 



The two aceofnpanying tables (figs. P, Q) serve to show the rela- 

 tionships of the bird and mammal faunas of the two regions, and the 

 nature of the occurrence of the various species in the Stikine Valley, 

 as observed by us. Certain ge|ieralizations may be drawn from these 

 tables. (1) There are, as previously remarked, more distinct types of 

 birds in the two contrasted regions than there are of mammals. (2) 

 There are more bird forms in the interior than on the coast. (In 

 addition, it may be said that bird life, as regards number of indi- 

 viduals, is far more abundant in the interior than on the coast.) (3) 

 In the Stikine Valley, at least, there are a number of species of the 

 interior that extend far toward the coast, while very few coastal races 

 extend any distance inland ; the fauna of the Sitkan district is closely 

 confined to the region west of the Coast Range. In certain respects 

 these tables are imperfect. It would take many seasons of field work 

 to fill in gaps in our knowledge that are here apparent. Also, in the 

 case of some species there are differences of altitude concerned (im- 

 plying zonal differences) as well as those of linear distance, and such 

 distinctions could not be made in this table. 



