_Scapanus townsendii_ _Citellus beecheyi_ _Scapanus orarius_ _Tamias townsendii_ _Sorex trowbridgii_ _Sciurus griseus_ _Sorex vagrans_ _Glaucomys sabrinus_ _Canis lupus_ _Castor canadensis_ _Felis concolor_ _Microtus townsendii_ _Lynx rufus_ _Microtus oregoni_ _Mephitis mephitis_ _Ondatra zibethicus_ _Spilogale gracilis_ _Zapus princeps_ _Procyon lotor_ _Odocoileus hemionus_ _Ursus americanus_ The following mammals are subspecifically distinct in western Washington and western Oregon: WASHINGTON OREGON _Sorex bendirii bendirii_ _Sorex bendirii palmeri_ _Sorex obscurus setosus_ _Sorex obscurus bairdi_ _Neotoma cinerea occidentalis_ _Neotoma cinerea fusca_ _Peromyscus maniculatus austerus_ _Peromyscus maniculatus rubidus_ _Clethrionomys californicus _Clethrionomys californicus occidentalis_ californicus_ _Microtus longicaudus macrurus_ _Microtus longicaudus abditus_ _Aplodontia rufa rufa_ _Aplodontia rufa pacifica_ The following species are found in western Oregon but do not occur in western Washington: _Vulpes fulva_ _Phenacomys albipes_ _Urocyon cinereoargenteus_ _Microtus canicaudus_ _Neotoma fuscipes_ _Thomomys bulbivorus_ _Phenacomys silvicola_ _Lepus californicus_ _Phenacomys longicaudus_ _Sylvilagus bachmani_ Several of these mammals which occur south of the river but not north of it are common on the south bank, a few miles from favorable but uninhabited territory on the north. Seemingly the pre-Vashon faunas of western Oregon and Washington were similar. Some species became extinct in Washington in the course of Vashon isolation. Others persisted. The very close relationship of the mammals of the first group indicates some crossing of the river. The best known of such crossings was that of the Beechey ground squirrel which, previous to 1915, was unknown in Washington. In 1915, when there was no man-made bridge at White Salmon, it crossed the river and since has spread over an area of at least 50 square miles. The distribution of the mountain beavers is unusual in that the form in the lowlands of Washington is indistinguishable from the subspecies in the Cascades of Oregon.