Chapter II: Part 2

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SPECIES AND SUBSPECIES. | A | B | C | D | E | F
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Neurotrichus gibbsii gibbsii | | | | | ? | C
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gibbsii minor | A | | | | |
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Scapanus townsendii | A | | | | |
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orarius orarius | A | | | | |
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orarius schefferi | | | | C | |
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orarius yakimensis | | | | A | |
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Sorex cinereus cinereus | | R | | | R |
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cinereus streatori | R | | | | |
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merriami merriami | | | | R | |
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trowbridgii trowbridgii | A | | | | C |
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trowbridgii destructioni | A | | | | |
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vagrans vagrans | A | | | | R |
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vagrans monticola | | C | C | A | C |
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obscurus obscurus | | | | | R |
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obscurus setosus | C | | | | C | A
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palustris navigator | | | | | C | A
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bendirii bendirii | A | | | | C |
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bendirii albiventer | C | | | | |
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Microsorex hoyi washingtoni | | R | | | |
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Myotis lucifugus carissima | | | C | C | |
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lucifugus alascensis | A | | | | C |
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yumanensis sociabilis | | | C | C | |
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yumanensis saturatus | A | | | | |
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keenii keenii | R | | | | R |
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evotis evotis | | R | | | |
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evotis pacificus | R | | | | |
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thysanodes thysanodes | | | | R | |
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volans longicrus | C | | | | |
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volans interior | | C | | | |
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californicus californicus | | | R | R | |
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californicus caurinus | A | C | | | |
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subulatus melanorhinus | | | R | A | |
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Lasionycteris noctivagans | A | A | | | C |
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Corynorhinus rafinesquii townsendii | R | | | | |
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rafinesquii intermedius | | R | | | |
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Pipistrellus hesperus hesperus | | | | R | |
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Eptesicus fuscus bernardinus | A | A | | | |
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Lasiurus cinereus cinereus | R | R | R | R | |
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Antrozous pallidus cantwelli | | | R | R | |
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Ursus americanus altifrontalis | A | C | | | A | A
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americanus cinnamomum | | A | | | C |
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chelan | | | | | R |
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Procyon lotor psora | A | | | | C |
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lotor excelsus | | R | R | C | |
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Martes caurina caurina | | | | | A | C
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caurina origenes | | | | | A | C
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pennanti | R | | | | R |
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Mustela erminea invicta | | C | | | C |
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erminea gulosa | | | | | C | C
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erminea murica | | R | | | |
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erminea fallenda | R | | | | |
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erminea streatori | R | | | | C |
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erminea olympica | R | | | | |
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frenata nevadensis | | C | C | C | C |
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frenata effera | | A | C | C | C |
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frenata washingtoni | | | | | C | C
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frenata altifrontalis | A | | | | C | C
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vison energumenos | C | C | C | C | C |
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Gulo luscus luteus | | | | R | R | R
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Lutra canadensis pacifica | C | R | R | R | C |
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Spilogale gracilis saxatilis | | | R | R | |
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gracilis latifrons | A | | | | |
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Mephitis mephitis hudsonica | | A | | | |
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mephitis major | | | R | R | |
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mephitis notata | | C | R | | |
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mephitis spissigrada | A | | | | |
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Taxidea taxus taxus | | C | C | C | R |
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Vulpes fulva cascadensis | | | | | | R
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Canis latrans lestes | C | A | A | A | C | R
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latrans incolatus | | A | C | C | A |
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lupus fuscus | R | R | R?| | R |
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Felis concolor missoulensis | | C | | | C |
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concolor oregonensis | C | C | | | C |
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Lynx canadensis | | | | | R |
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rufus fasciatus | A | | | | C |
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rufus pallescens | | A | C | C | C |
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Tamias minimus scrutator | | | | C | |
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minimus grisescens | | | | R | |
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amoenus caurinus | | | | | A | A
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amoenus felix | | | | | A | A
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amoenus ludibundus | | | | | A | A
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amoenus affinis | | A | | | |
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amoenus canicaudus | | A | | | |
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amoenus luteiventris | | C | | | A |
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ruficaudus simulans | | C | | | A |
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townsendii townsendii | A | | | | |
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townsendii cooperi | | C | | | A | R
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Marmota monax petrensis | | | | | R |
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flaviventris avara | | R | C | A | |
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caligata cascadensis | | | | | R | A
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olympus | | | | | C | A
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Citellus townsendii townsendii | | | | A | |
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washingtoni | | | C | A | |
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columbianus columbianus | | A | C | | |
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columbianus ruficaudus | | A | | | |
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beecheyi douglasii | | A | | | |
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lateralis tescorum | | | | | C |
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lateralis connectens | | | | | C |
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saturatus | | C | | | A |
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Tamiasciurus hudsonicus richardsoni | | A | | | A |
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hudsonicus streatori | | A | | | A | R
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douglasii douglasii | A | A | | | A | C
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Sciurus griseus griseus | C | C | | | |
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Glaucomys sabrinus oregonensis | C | | | | |
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sabrinus fuliginosus | | | | | A |
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sabrinus columbiensis | | A | | | |
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sabrinus latipes | | A | | | A |
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sabrinus bangsi | | R | | | C |
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Perognathus parvus parvus | | | C | A | |
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parvus lordi | | | C | A | |
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parvus columbianus | | | | A | |
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Dipodomys ordii columbianus | | | | A | |
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Thomomys talpoides devexus | | | | A | |
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talpoides columbianus | | | | A | |
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talpoides aequalidens | | | A | | |
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talpoides wallowa | | | | | A |
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talpoides fuscus | | A | C | R | C | C
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talpoides yakimensis | | | C | A | |
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talpoides shawi | | | | | C | A
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talpoides immunis | | | | | A | A
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talpoides limosus | | C | A | | |
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talpoides douglasii | A | | | | |
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talpoides glacialis | A | | | | |
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talpoides tacomensis | A | | | | |
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talpoides pugetensis | A | | | | |
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talpoides tumuli | A | | | | |
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talpoides yelmensis | A | | | | |
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talpoides couchi | A | | | | |
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talpoides melanops | | | | | C | A
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Castor canadensis leucodonta | A | A | | C | C |
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canadensis idoneus | A | | | | |
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Onychomys leucogaster fuscogriseus | | | | A | |
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Reithrodontomys megalotis megalotis | | | C | A | |
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Peromyscus maniculatus oreas | A | | | | A | A
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maniculatus hollisteri | A | | | | |
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maniculatus austerus | A | | | | |
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maniculatus rubidus | A | | | | |
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maniculatus gambelii | | C | R | A | |
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maniculatus artemisiae | | A | R | R | C | C
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Neotoma cinerea occidentalis | | C | R | A | C | A
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cinerea alticola | | C | | | A | C
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Synaptomys borealis wrangeli | | | | | | A
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Phenacomys intermedius intermedius | | | | | C | A
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intermedius oramontis | | | | | C | A
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Clethrionomys gapperi saturatus | | R | | | A | A
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gapperi idahoensis | | R | | | A | A
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gapperi nivarius | | | | | A | A
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californicus occidentalis | A | | | | |
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Microtus pennsylvanicus funebris | | A | R | | C |
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pennsylvanicus kincaidi | | | | A | |
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montanus nanus | | | A | C | |
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montanus canescens | | C | A | A | |
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townsendii townsendii | A | | | | |
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townsendii pugeti | A | | | | |
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longicaudus halli | | A | C | C | C |
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longicaudus macrurus | R | | | | C | A
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richardsoni arvicoloides | | | | | C | A
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richardsoni macropus | | | | | C | A
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oregoni oregoni | A | | | | A |
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Ondatra zibethicus osoyoosensis | A | A | | C | |
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zibethicus occipitalis | A | | | | |
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Zapus princeps oregonus | | | | | A |
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princeps kootenayensis | | | | | A |
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princeps idahoensis | | | | | A |
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princeps trinotatus | A | | | | C | A
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Aplodontia rufa rufa | A | | | | |
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rufa rainieri | | | | | A |
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Erethizon dorsatum epixanthum | | A | R | C | A | R
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dorsatum nigrescens | | A | R | C | A | R
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Ochotona princeps cuppes | | | | | | A
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princeps fenisex | | | | | | A
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orinceps brunnescens | | | | | C | A
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Lepus townsendii townsendii | | | C | A | |
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californicus deserticola | | | C | A | |
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americanus washingtonii | A | | | | A |
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americanus cascadensis | | C | | | A | C
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americanus pineus | | C | | | A | C
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americanus columbiensis | | A | | | |
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Sylvilagus nuttallii nuttallii | | | | A | |
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idahoensis | | | | A | |
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Cervus canadensis roosevelti | A | | | | A | R
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canadensis nelsoni | | C | | | A |
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Odocoileus virginianus leucurus | A | | | | |
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virginianus ochrourus | | A | | | |
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hemionus hemionus | | A | | | A | C
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hemionus columbianus | A | | | | C |
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Ovis canadensis canadensis | | A | A | A | A | A
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canadensis californiana | | A | A | A | A |
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Oreamnos americanus americanus | | | | | | A
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GEOLOGIC HISTORY OF WASHINGTON

The composition of the mammalian fauna of any area is dependent on several factors. These include the composition of the original fauna, species which have since invaded the area, and quantitative and qualitative changes that have occurred in the area. The latter two factors refer to changes in relative numbers or extermination of species through environmental changes or competition with other forms and evolutionary changes that have occurred in the species making up the mammalian fauna.

Our knowledge and understanding of the distribution and history of the species of mammals occurring in Washington decreases rapidly as we go back in time. The distribution of the modern fauna at the present time is fairly well known. The distribution of species 100 years ago is less well understood. This is especially true of certain game species and carnivores whose distribution has been altered by man. Our knowledge of the distribution of mammals in the Pleistocene and earlier times is based on fossil skeletons. Such knowledge must necessarily be meager, for conditions favorable to fossilization and the preservation of fossils until their subsequent discovery by man, were not of common occurrence.

In the Cascades and in eastern Washington, the Miocene was a time of orogeny and great volcanism. Great flows of lava, 4,000 feet thick in the Snake River area (Russell, 1893), emerging from fissures in the Snake River area, formed the Columbian Plateau. The Columbian basalt slopes inward centripetally from the eastern, northern, and western margins of the Columbian Plateau with an average descent of 25 feet to the mile (Flint, 1938). The dip of the lava flows results in the basalt-marginal course of the Spokane and Columbia rivers today, along the northern edge of the Columbian Plateau. The earlier part of the Pliocene was a period of erosion and deformation. In the early Pleistocene the five great volcanic cones of the Cascades, Mount Baker, Glacier Peak, Mount Rainier, Mount Adams and Mount St. Helens were formed. In eastern Washington a gentle folding of the Miocene lava flows occurred. The folding took place slowly and the Columbia River in its course along the eastern edge of the Cascades cut through the folds as they formed, making a series of water gaps. Farther south, the Simcoe-Frenchman Hills anticline seems to have arisen more rapidly and the Columbia River was forced eastward before it became impounded and rose over the barrier and plunged down, tearing out the great Wallula Water Gap (Flint, 1938). This gap is a mile wide, eight miles long and, in places, a thousand feet deep. The impounding of the Columbia by the Simcoe-Frenchman Hills anticline resulted in a lake several hundred miles in area. Sediments deposited in this lake form the Ringold formation. The Ringold formation possesses a very early Pleistocene mammalian fauna.

The Pleistocene was a time of great change in the mammalian fauna of the world. Unfortunately the beautiful glacial sequence revealed in Europe and the Mississippi Valley cannot be detected in Washington. In western Washington the deposits of the last continental glaciation and fluvial deposits of the last interglacial period almost everywhere obscure evidence of earlier glaciations. Deposits of an earlier glaciation, named Admiralty by Bretz (1913), have been detected in places. Deposits of greater age, that may represent a still earlier glaciation, have been noted. In eastern Washington the only definite proof of multiple glaciation is of one glaciation preceding the last. This is the Spokane glaciation of Bretz (1923). That multiple glaciation in the sequence reported from the Mississippi Valley affected Washington seems probable. The lack of evidence of a complete sequence is negative evidence. In western Washington the earliest glacial deposits might be beneath the later deposits or they may have been removed or reworked by subsequent glaciations, whereas in eastern Washington they may have been removed by subsequent glaciation and erosion.

The time interval between the two known glaciations appears to have been of greater duration than the Recent. The drift of the earlier period is sometimes found covered by the till of the later glaciation, and preserved by it. The early material is deeply weathered and all save the hardest pebbles and quartzites, for example, are rotten and disintegrate at the touch. In contrast, the later deposits are almost unweathered. Pebbles are hard, and ring when struck. A zone of leaching and oxidation of the finer materials reaches a depth of some 30 inches, below which the till is fresh.

Two names are currently applied to the last continental glaciation of the state of Washington. That west of the Cascade Mountains, studied and described by Bretz (1913), was termed "Vashon." The interglacial cycle preceding it was called "Puyallup." The glaciation of eastern Washington has been called "Wisconsin," after the Mississippi Valley terminology, by several writers. Papers by Flint (1935, 1937) describe and map it.

The Vashon and Wisconsin glaciations probably occupied the same time interval, although this has not certainly been established. In the present report I have used the term "Vashon-Wisconsin" in speaking of the entire period, or the glaciers both east and west of the Cascades together. Vashon, alone, is restricted to western Washington and Wisconsin to eastern Washington.

The Vashon glaciation seems to have consisted of an ice dome centering in Puget Sound (the Puget Glacier of Bretz, 1913) and flooding the lowlands from the Olympic Mountains to the Cascade Mountains. The southern edge of the Puget Glacier was slightly south of the present terminus of Puget Sound. Fingerlike projections of ice were forced up valleys of the western Cascades and the northern and eastern Olympics. Some of these upward moving fingers of ice met and coalesced with valley glaciers descending from the mountains. At the southern edge of the glacier, the Black Hills and Porcupine Hills remained above the ice although partially surrounded by it.

The Wisconsin glacier, according to Flint (1935), was a great piedmont glacier, fed by valley glaciers from the Cascades and Coast Ranges to the west and the Rockies to the east. It extended from the Idaho boundary to the Cascade Mountains. From the Canadian Boundary it sloped down to an approximate elevation of some 6500 feet at Republic and to 2500 feet on the northern edge of the Columbian Plateau which was the southern edge of the glacier. The Kettle River Mountains, in almost the center of the glacier, remained a peninsula or driftless area that divided the glacier into two lobes. The Pend Oreille, Huckleberry and other mountain ranges, formed nunataks, or islands above the ice, at the southern part of the glacier.

The behavior of valley glaciers in the northern Cascade Mountains during Vashon-Wisconsin time, seems to have been variable. Some depression of the snow line, at least in the north, seems probable.

The Vashon Glacier impinged on the eastern, northern and to some extent the western, slopes of the Olympic Mountains. Late Pleistocene valley glaciers in the Olympics, however, seem to have been inconsequential.

The time of the retreat of the Vashon-Wisconsin glaciers is a subject of special interest to the mammalogist in that it represents time for invasion and dispersal of species and in that it represents generations of individuals upon which natural selection might act. It is generally agreed that a period of approximately ten thousand years has elapsed since the retreat of the Vashon-Wisconsin glaciers from Washington.

Information on the climate of the state of Washington previous to the period of the last continental glaciation is understandably meager. Bretz (1913) considers the Puyallup period a time of excessive precipitation and erosion. Bits of lignite from Puyallup sediments seem to be of Douglas fir. Presumably the climate was slightly warmer and more humid than it is today. Vegetation possibly consisted of coniferous forests.

With the advance of the Vashon ice, mammals north of the ice border were all or mostly eliminated. Climatic conditions south of the border of the ice probably were strongly affected by it. Remains of mammoths have been found in Vashon till. The presence of many non-boreal species of mammals in southwestern Washington indicates their persistence there and that conditions therefore were not intolerable for them. Probably the climate of southwestern Washington was cool and dry. Fir, spruce, and Douglas fir may have been the dominant trees. Hansen (1941 A: 209) found evidence from studies of pollen that coniferous forests were growing in west-central Oregon in late glacial time. These pollen studies of postglacial peat bogs by Henry P. Hansen give evidence of postglacial climatic changes. Hansen points out (1941 B, 1941 C) that climatic changes west of the Cascades were probably slight because of the influence of the Pacific Ocean. Pollen profiles indicate an early, cool, dry climate followed by a warmer one and increasing humidity. The present climate may be considered cool and humid. Most of western Washington lies in the Humid subdivision of the Transition Life-zone.

The pre-Wisconsin climate of eastern Washington is unknown. From the loessial nature of the Palouse Soil (Bryan, 1927), a preglacial deposit, the area would seem to have been arid, probably a grassland or a sagebrush desert. If the fossil fauna discovered at Washtuckna Lake, Adams County, is of this period, the forest conditions of the Blue Mountains were slightly more extensive than at present. The glacial climate of the Columbian Plateau in Wisconsin time was probably cool and arid. Pollen studies by Hansen (1939, 1940) indicate increasing dryness and warmth since the retreat of the Wisconsin ice. Present-day climate on the Columbian Plateau is warm and dry. The plateau is principally a sagebrush desert. The glaciated area to the north is cooler and more humid, supporting extensive forests of yellow pine and other conifers.

THE FAUNAS

We have mentioned elsewhere that three different mammalian faunas occur in Washington. These may be described as follows.

1. THE GREAT BASIN FAUNA. This fauna is best typified by such genera as _Perognathus_ and _Dipodomys_. Species that, at least in Washington, are confined to this fauna are:

_Sorex merriami_ _Tamias minimus_
_Myotis thysanodes_ _Perognathus parvus_
_Myotis subulatus_ _Dipodomys ordii_
_Pipistrellus hesperus_ _Onychomys leucogaster_
_Antrozous pallidus_ _Reithrodontomys megalotis_
_Taxidea taxus_ _Lagurus curtatus_
_Marmota flaviventris_ _Lepus californicus_
_Citellus townsendii_ _Sylvilagus nuttallii_
_Citellus washingtoni_ _Sylvilagus idahoensis_

The break between the Great Basin Fauna and the other two faunas is extremely sharp, probably as a consequence of a sharp break in the flora.

2. THE PACIFIC COASTAL FAUNA. The mammals of the humid coastal district range from the Fraser River, British Columbia, southward to the vicinity of Monterey Bay, California. In Washington typical genera are _Aplodontia_, _Neurotrichus_ and _Scapanus_. The following species are typical of the Pacific Coastal Fauna in Washington:

_Neurotrichus gibbsii_ _Tamiasciurus douglasii_
_Scapanus townsendii_ _Sciurus griseus_
_Sorex trowbridgii_ _Clethrionomys californicus_
_Sorex bendirii_ _Microtus townsendii_
_Marmota olympus_ _Microtus oregoni_
_Tamias townsendii_ _Aplodontia rufa_

Some species which range outside this faunal area have strongly marked races confined to it. _Glaucomys sabrinus oregonensis_ and _Lepus americanus washingtonii_ are examples. The Pacific Coastal Fauna is a forest fauna. Like the Great Basin Fauna, it reaches its northern limit of distribution in Washington and is better represented farther south. Unlike the Great Basin Fauna, the break between the Pacific Coastal and the surrounding fauna is not sharp, because forests continue into the more boreal faunal areas to the north and east. There, some mingling of coastal and Rocky Mountain faunas occurs.

3. ROCKY MOUNTAIN FAUNA. If this fauna be thought of as including mammals of the Rocky Mountains of the United States, and also those of the subarctic faunal area to the east of these mountains in Canada, the species in Washington are as follows:

_Sorex palustris_ _Synaptomys borealis_
_Microsorex hoyi_ _Phenacomys intermedius_
_Lynx canadensis_ _Clethrionomys gapperi_
_Marmota caligata_ _Microtus richardsoni_
_Citellus lateralis_ _Ochotona princeps_
_Citellus columbianus_ _Lepus americanus_
_Tamias amoenus_ _Rangifer montanus_
_Tamiasciurus hudsonicus_ _Oreamnos americanus_
_Glaucomys sabrinus_

Of the three, the Great Basin Fauna is the most distinct. Only about twenty species which occur within the Great Basin Faunal Area, occur also outside of it in one or both of the two other faunal areas. Most of these twenty are subspecifically different in the Great Basin Faunal Area as contrasted with one or both of the other areas. Each of the other two areas has no less than 32 species that are not restricted to it.

SPECULATION AS TO EMIGRATIONAL HISTORY OF THE MAMMALS

The present fauna of the state of Washington was derived in part from Asia and in part from native forms. Great changes occurred in early Pleistocene through emigration. By the late Pleistocene most of the mammals now occurring in the state of Washington were as they are today. The greatest changes that seem to have occurred in the late Pleistocene are the extinctions of numerous groups, locally or totally. Among the carnivores, Matthew (1902: 321) reports remains of the great lion, _Felis atrox_, associated with such familiar species as the badger, cougar, lynx and mountain goat. The great lion was very similar to the modern African lion but was fully a fourth larger. Associated with the great lion in the California tar pits are the carnivorous short-faced bears (_Tremarctotherium_), as large as the Alaskan brown bears; dire wolves (_Aenocyon_), larger than timber wolves; and saber-tooth tigers (_Smilodon_). These forms were probably also present in Washington in the late Pleistocene. Matthew (_loc. cit._) reports remains of the giant beaver, _Castoroides_, from the Silver Lake deposit of Oregon. This great beaver, as large as a black bear, was doubtless a resident of Washington also. Peccaries, camels, bison, horses and giant ground sloths have been recorded from Pleistocene deposits of Washington and nearby areas. Of the elephant tribe, the mastodon and several species of mammoths were present.

These extinct forms have doubtless exerted some influence on the past distribution of mammals in Washington and possibly have had an effect on the distribution of members of the living fauna. One species of the mammoth, at least, existed in Washington in postglacial time. Remains of this form, _Elephas columbi_, have been found in Vashon till.

The three faunas of Washington can be placed in two categories. One is Sonoran, essentially a desert type, and occupies the Columbian Plateau. The other two are forest faunas, predominantly boreal in complexion, and are closely related. The Rocky Mountain Fauna is found in the Blue Mountains and in northeastern Washington. The Pacific Coastal Fauna is found in western Washington.

The ice sheets of Vashon-Wisconsin time descended southward to southern Puget Sound and to the northern edge of the Columbian Plateau. If the area of the ice sheet be superimposed on a map of distributional areas of Washington, it is seen that the area occupied by the Rocky Mountain Fauna in northeastern Washington is eliminated. Thus, at the maximum descent of Wisconsin ice, the Rocky Mountain type of mammalian fauna was found only in extreme southeastern Washington. No point of contact between the forest fauna of the Rocky Mountains and the fauna of the Pacific coast exists, anywhere, because desert areas, or at least barren plains, lie between them from the border of the glaciers south to Mexico. For the entire period, perhaps thousands of years long, while the glaciers were in place, the two forest faunas were separated. Repeated separation of the faunas by successive glaciations is thought to be responsible for many of the differences now existing between them.

Following the retreat of the ice, the Pacific Coastal Fauna extended its range northward to the Fraser River and, in part, into the Cascade Mountains. The Rocky Mountain Fauna invaded northeastern Washington and boreal Canada, including the Pacific Coast north of the Fraser River. Certain parts of the Rocky Mountain Fauna also invaded the Cascade Mountains.

Inasmuch as the Cascades were invaded by species from both faunas, a detailed analysis of the mammals existing there now seems justified. Several significant features of the composition of the mammal fauna of the Cascades are apparent. First, several species typical of the Pacific Coastal Fauna are present, such as _Neurotrichus gibbsii_, _Sorex trowbridgii_, _Sorex bendirii_, _Tamias townsendii_, _Microtus oregoni_ and _Aplodontia rufa_. Each of these species has no close relatives in the Rocky Mountain Fauna and, save perhaps _Sorex trowbridgii_, occupies a unique ecological niche and has no counterpart in the Rocky Mountain Fauna.

A second group includes species with close relatives in both the Rocky Mountain and Pacific Coastal faunas. This group is remarkable in that it is composed of either very closely related species or very strongly differentiated subspecies in each fauna. For example, the golden-mantled ground squirrel (_Citellus saturatus_) of the Cascade Mountains is specifically distinct from _Citellus lateralis_. Supposedly the Cascade form was isolated in the southern Cascades during Vashon-Wisconsin time. The Douglas squirrel (_Tamiasciurus douglasii_) of the Cascades, which has a red belly, is the same as the squirrel of the lowlands of western Washington but is specifically distinct from the red squirrel (_Tamiasciurus hudsonicus_) of the Rocky Mountain Fauna, which has a white belly. In the extreme northeastern Cascades the two species come together. They do not interbreed but seem to compete, for they do not occur together. The flying squirrel (_Glaucomys sabrinus fuliginosus_) of the Cascades is only slightly differentiated from other races of the Rocky Mountain Fauna but is much different, as are all Rocky Mountain races, from the western Washington subspecies (_Glaucomys s. oregonensis_). The red-backed mouse of the Cascades is _Clethrionomys gapperi_, a species distinct from _Clethrionomys californicus_ of western Washington. The jumping mouse of the Cascades is _Zapus princeps trinotatus_, the same race that occurs in western Washington. It is quite distinct from, and has previously been considered a species separate from, the races of the Rocky Mountain Fauna. The snowshoe rabbit of the Cascades is closely related to other races of the Rocky Mountain Fauna but is distinct from _L. a. washingtonii_ of western Washington. The pika (_Ochotona princeps_) of the Cascades was apparently isolated in the southern part of the range during the glaciation. After the retreat of the glaciers it extended its range northward. Competition between two subspecies has resulted in parallel distributions due to relative body size. The two races freely intergrade and the differences between them are not so great as in the other forms mentioned.

The third group of mammalian species of the Cascades is composed of species typical of the Rocky Mountain Fauna such as: _Marmota caligata_, _Synaptomys borealis_, and _Orcamnos americanus_. Each has no ecological counterpart in the Pacific Coastal Fauna. Each is absent from the Cascades of Oregon.

We interpret the mixture of faunas in the Cascades as follows: The Vashon-Wisconsin ice sheet was in place for a long period of time, longer, probably, than the Recent. During this time, forest mammals of the Pacific Coast were isolated from forest mammals farther east by glaciers to the north and desert to the east. Changes took place in both of the separated forest faunas. Certain species, perhaps, such as the mammoth, became extinct. Other forms were exterminated then or at an earlier time in one fauna or the other. If _Aplodontia_, _Neurotrichus_ or _Scapanus_ occurred in the Rocky Mountain faunal area, it lived in an inland area of rigorous climate, and disappeared there because it was unable to adapt itself to the cold. In the mild climate caused by proximity of the ocean, mild even in Vashon-Wisconsin time to judge from evidence yielded by study of fossil pollens, primitive forms such as moles, the Bendire shrew, and mountain beaver persisted along the coast, where there were no boreal conditions. Some alpine forms, such as _Marmota olympus_, _Ochotona princeps brunnescens_ and _Citellus saturatus_ persisted in the Olympic or Cascade mountains as relic species. On the whole, however, the glacial divergence resulted in a boreal forest fauna and a temperate forest fauna.

In addition to change in component species, there were evolutionary changes in the species themselves. In some these were considerable, as shown by the differences between related forms of the two faunas. In most species, however, evolutionary changes have resulted in only subspecific differences.

Following the retreat of the glaciers and the establishment of vegetation on the deglaciated areas, movements of the faunas occurred. The Rocky Mountain Fauna spread northward and westward, to northeastern Washington and, in Canada to the Pacific, occupying most of the land exposed by the glaciers. The Pacific Coastal Fauna spread northward only as far as the relatively slight barrier of the Fraser River. The Cascade Mountains became a "no-man's land." The pika and golden-mantled ground squirrel of the southern Cascades spread northward. Boreal Rocky Mountain forms with no ecologic competitors from the Pacific Coastal Fauna occupied the Cascades. Also, coastal species with no Rocky Mountain competitors occupied the Cascades. Nevertheless, some competition between members of the two faunas ultimately occurred, and in instances where closely related forms occurred in the two faunas, one or the other prevailed in the Cascade Range. For example, the Douglas squirrel and big jumping mouse are now established in that range, but the relative of each occurring in the Rocky Mountains is present in the extreme northeastern Cascades. It is possible that in these two cases, the related form occurring in the Rocky Mountains has just entered the area and that competition has just begun. With regard to the flying squirrel, red-backed mouse and snowshoe rabbit, the more boreal Rocky Mountain representatives have definitely displaced the coastal forms.

Certain mass movements of mammals are popularly believed to have occurred with the advance of the ice sheets of the Pleistocene. The boreal birds and plants on higher peaks of the Cascades and the Sierra Nevada of California are thought to represent relics of faunas that moved northward. Such mass movements probably did occur and there is some evidence of their occurrence in Washington. Probably the pre-Wisconsin flora of coastal British Columbia consisted of coniferous forest similar to that of western Washington today. If this were the case, the mammalian species in British Columbia corresponded closely to those of western Washington. An influx of such a fauna into coastal Washington would scarcely be evident today if, indeed, it was noticeable even then. In eastern Washington, forest species forced southward would come upon the barren, inhospitable plains and deserts of the Columbian Plateau.

The greater part of the southward moving forms found refuge in the Cascade Mountains where, for most of Wisconsin time, they were isolated in the southern Cascades. Examples are _Sorex palustris_, _Martes caurina_, _Martes pennanti_, _Gulo luscus_, _Vulpes fulva_, _Lynx canadensis_, _Tamias amoenus_, _Thomomys talpoides_ (_douglasii_ group), _Phenacomys intermedius_, _Microtus richardsoni_ and _Ochotona princeps_. In each of these species little or no subspecific variation has occurred between the populations in the Cascades of Washington and the Cascades of Oregon.

While the ice sheet existed in Washington there may have been relatively little movement of the mammalian fauna. There is definite evidence of a brief contact between the Rocky Mountain Fauna of the Blue Mountains and the fauna of the southern Cascades. For example, the pocket gopher of southeastern Washington (_Thomomys talpoides aequalidens_) is most closely related to the gopher of the Simcoe Anticline, and the long-tailed meadow mouse (_Microtus longicaudus halli_) of the Blue Mountains closely resembles the meadow mouse of the Yakima Valley.

Mammals of the Blue Mountains and those of the southern Cascades may have come into contact on the Simcoe-Horseheaven Hills Anticline, which now stretches 150 miles from the Cascades to the Wallula Water Gap. Excepting the easternmost 40 miles, it is timbered. East of the Columbia, a continuation of the anticline and other hills reaches to the Blue Mountains. Supposedly, in Wisconsin Time, this anticline possessed a more humid climate and the habitat was essentially the same as that of an alpine meadow today. The forms on the two ends of the anticline that are closely related inhabit humid, meadow habitat. In an earlier paper, Dalquest and Scheffer (1944: 316) named this connection the Simcoe Bridge. Its existence was so strongly indicated by the distribution of pocket gophers in Washington that we supposed that the study of many other species would show that they crossed this bridge. However, study of additional species shows that for them the Simcoe Bridge was of only slight importance; there appears to have been but little mingling of the fauna of the Blue Mountains and the Cascades by way of the bridge. The Columbia River probably acted as an effective barrier to many forms that might otherwise have utilized it. The forms that did cross on this bridge are species known to be active in winter and to emigrate over considerable areas through tunnels under the snow (Davis, 1939: 257). The pocket gopher and long-tailed meadow mouse may have crossed the Columbia, under a cover of snow, when the river was frozen over. The Columbia has frozen over at the Wallula Water Gap in historic times.

Great movements of mammal species came after the retreat of the Vashon-Wisconsin ice. The greatest of these was the spread of the Rocky Mountain Fauna northward and eastward to the Pacific. In this process, northeastern Washington was inhabited by animals that probably came from Idaho and Montana. Some of the species from farther north, as for example the caribou, may first have been forced into Idaho and Montana by the glaciers. The invasion of northeastern Washington probably was not a mass movement of an entire fauna, because invasion seems to be still going on. As yet the woodchuck and striped ground squirrel of the Pend Oreille Mountains have not crossed the Columbia River, a relatively minor barrier in northeastern Washington. The mountains west of the Columbia are occupied instead by the yellow-bellied marmot, a member of the Great Basin Fauna, and there is no ecologic counterpart in these mountains of the golden-mantled ground squirrel.

Also the invasion of the Cascade Mountains by a number of Rocky Mountain species may have been an intermittant or gradual movement. The red squirrel and Rocky Mountain subspecies of jumping mouse now are present in the extreme northeastern Cascades, where they possibly arrived relatively recently. The squirrel is competing with the coastal species already present and may eventually supplant it. The same may be true of the two forms of jumping mouse.

The invasion by the Rocky Mountain Fauna was rapid as compared with that of the Pacific Coastal Fauna. Evidence of this was presented in an earlier paper (Dalquest and Scheffer, 1944: 310), where it was shown that the gophers of the _douglasii_ group, isolated during the Vashon time in the southern Cascades, made only a few feeble postglacial movements and then only when conditions were ideal. In this same time the _fuscus_ group of gophers moved from Idaho and virtually surrounded the range of the _douglasii_ group. This tendency to immobility seems to have been characteristic of every member of the Pacific Coastal Fauna. If the retreat of the Vashon and Wisconsin glaciers occurred at the same time, both faunas had an equal opportunity to invade the deglaciated area. Yet, the Pacific Coastal Fauna actually moved northward along the coast only to the Fraser River area, and slightly farther in the Cascades.

Possibly the two glaciers retreated at different times. The Wisconsin Glacier was a piedmont glacier, fed by valley glaciers to the west and east, and may have disappeared when the feeder glaciers dried up. The Vashon Glacier was instead an ice cap, supposedly self-supporting much in the same manner as is the Greenland Ice Cap, and may have persisted longer than the Wisconsin glacier. If it did persist longer it formed a barrier to the northward emigration of coastal species of mammals.

Possibly, also, the whole of the Pacific Coastal Fauna possessed an inherent sluggishness resulting from their long residence in the uniform climate and habitat of the Pacific Coast. Certainly the species show today great habitat specialization as compared with species of the Rocky Mountain Fauna. Also, there are fewer individual mammals per unit of area in western Washington than in northeastern Washington. The persistence of the Vashon Glacier, an inherent lack of incentive to emigrate, or retention of a favorable environment, may account for the relatively small area invaded by the Pacific Coastal Fauna.

The Olympic Mountains, on the Olympic Peninsula, rise above the timber-line and are surrounded by forested lowlands which in a sense isolates this mountain range. Early workers, notably Elliot, obtained specimens of mammals from the Olympics and described numerous races, principally, it appears, on the supposition that because the range was somewhat isolated it should possess a unique fauna. Subsequent revisions of groups of mammals have indicated that most of the names proposed, on the basis of specimens from the Olympics, were either invalid or pertained to mammals found also in the Cascades.

The mammals of the Olympic Peninsula appear to be divisible into three groups. A majority of them fall within the first group, namely coastal races possessing wide ranges in the lowlands of western Washington. The second group consists of species of the Rocky Mountain Fauna but with close relatives in the Cascades. The third group includes but two forms, both unique and found only on the Olympic Peninsula.

The first group includes nonalpine forms of the lowlands surrounding the Olympic Mountains. For the most part these are identical with races of the Puget Sound area. A few are slightly differentiated from the mammals of the Puget Sound area but are the same as mammals from southwestern Washington. As will be shown later, some differentiation in the Pacific Coastal Fauna has occurred. This is thought to be evolution _in situ_, rather than the result of mass movements. Many nonalpine Coastal mammals occur in alpine habitat in the Olympics.

The second group consists of species of the Rocky Mountain Fauna. Their relationship to the mammals of the Cascades is indicated in the two parallel columns below.

OLYMPICS CASCADES

_Sorex palustris navigator_ _Sorex palustris navigator_
_Martes caurina caurina_ _Martes caurina caurina_
_Martes pennanti_ _Martes pennanti_
_Tamias amoenus caurinus_ _Tamias amoenus ludibundus_
_Phenacomys intermedius oramontis_ _Phenacomys intermedius oramontis_
_Clethrionomys gapperi nivarius_ _Clethrionomys gapperi saturatus_

Only two of these are racially distinct from their relatives in the Cascades. Of these the chipmunk is a plastic species and breaks down into many races in Washington. The chipmunks of the Olympics and of Mt. Rainier are so similar that Howell (1929: 77) considered them as identical and mapped Mount Rainier as an isolated part of the range of the Olympic form (see account of _T. a. caurinus_). The relationship of the red-backed mice, also, is close, but has been obscured by the usual assumption of relationship between _californicus_ (_occidentalis_) and _gapperi_. The principal difference between the alpine forms is the pallor of _nivarius_. This pallor of mammals in general from the Olympic Mountains is noteworthy, but in the red-backed mouse is exceptionally noticeable. This pallor is discussed beyond in the paragraphs dealing with differentiation. Mention should be made here of _Myotis keenii_. This is a species which seems to have extended its range to Washington from the north. The power of flight, of course, removes it from consideration in attempting to reconstruct routes followed by terrestrial mammals.

The route of the pocket gopher (_Thomomys_) in emigrating from the Cascades to the Olympics (Dalquest and Scheffer, 1944: 310), was over the outwash train of the Mount Rainier Glaciers, especially the Nisqualli Glacier, to the extensive outwash aprons of the Vashon Glacier around southern Puget Sound, and thence into the Olympic Mountains. Under the conditions in early postglacial time this invasion route, hereinafter termed the Puget Bridge, around the Pleistocene Lake Russell (present Puget Sound), is thought to have been mainly an alpine meadow. Indeed, the isolated prairies remaining today are the unforested remnants of the outwash aprons (see Dalquest and Scheffer, 1942: 69) and possess several species of alpine plants, notably the shooting star, camas, and bear grass.

If the Vashon Glacier remained in place considerably longer than the Wisconsin Glacier, these Rocky Mountain species may have invaded the Cascades from northeastern Washington and travelled around the southern edge of the Puget Glacier or of Lake Russell. The close relationship of the races involved, however, suggests that the emigration took place much more recently. The barriers to such movement even today are slight, consisting principally of narrow areas of forest. For the water shrew, an almost continuous water habitat still exists, by way of the Nisqualli River, streams in the Puget Sound area, and the Satsop River in the Olympics. Tree-living forms such as the fisher and marten might easily travel the intervening distance today, and, by going along the forests north of the Chehalis River, reach the Olympics without crossing more than small streams and virtually without descending to the ground. Chipmunks and mice probably utilized the prairie or meadow area of the Puget Bridge, as did the gophers.

Considering the long existence of the Puget Bridge, it is surprising that such forms as the pika, water rat and golden-mantled ground squirrel did not cross to the Olympics. These forms are, however, species of the higher or eastern slopes of the Cascades.

The third group of Olympic mammals includes the white-bellied water shrew and the Olympic marmot, both indigenous forms.

The Bendire water shrew, _Sorex bendirii albiventer_, is not restricted to alpine habitat but occurs throughout the Olympic Peninsula. Its nearest relative is _S. b. bendirii_ of the rest of western Washington. _S. b. albiventer_ differs from _bendirii_ only in possessing a partially white ventral surface. We can only conclude that the white belly of _albiventer_ is a mutation that the local environment has favored and that the characters have, therefore, spread through the population on the Olympic Peninsula. Occasional specimens are taken with dark bellies characteristic of _bendirii_ (Jackson, 1928: 199).

The Olympic marmot, _Marmota olympus_, specifically distinct, and apparently the only preglacial relic species of alpine mammal in the Olympics, is most nearly related to _Marmota vancouverensis_ of the unglaciated mountains of Vancouver Island, British Columbia. Both _olympus_ and _vancouverensis_ are close relatives of _Marmota caligata_ which ranges southward into the Cascades of Washington.

The Columbia River in its course westward through the Cascade Mountains, might be expected to act as a highway for the movement of mammals, but the extent to which it has done so seems to be slight, at least in postglacial time. The pocket gopher of southwestern Washington reached the area about Vancouver from the southern Cascades by way of meadows on the gravel terraces of Wisconsin glacial drift. No other mammal seems to have extended this far. Several Great Basin species, such as the cottontail, extend westward in the valley of the Columbia to the vicinity of Bingen.

The mammals of western Oregon and southwestern Washington are closely similar as are the plants and climate, despite the fact that the broad Columbia River courses through the area and did so all through Recent and Pleistocene times. Many species would be expected to have crossed this barrier by swimming and rafting, and that they did so is indicated by the large number of mammals which are identical or very closely related on the two sides of the river.

Mammals which seem not to differ on the two sides of the river include:

_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.

The mammals that are racially distinct on the two sides of the Columbia River merit careful scrutiny. The _Peromyscus_ of the two sides more closely resemble one another than those of southern Oregon resemble those of northern Oregon or than those of southern Washington resemble those of northern Washington. For _Peromyscus maniculatus_, the Columbia River is simply a convenient boundary for the separation of two slightly different races. The Oregon race of the bushy-tailed wood rat is a coastal type but the Washington form is the same as that of eastern Washington. Seemingly the more eastern race spread to an unoccupied habitat in western Washington. Other races that differ on the two sides of the Columbia probably developed while separated by the river.

The San Juan Islands now possess a limited mammalian fauna. Unfortunately the activities of man have somewhat changed the native populations, especially by the introduction of the domestic rabbit which is now a serious pest in the islands. The Douglas squirrel, present on Blakeley Island, is said to have been introduced and one resident claims to have first brought it to the island. Two different persons claim credit for introducing the Townsend chipmunk on Orcas Island but do not account for its presence on Lopez Island. The three mammals most abundant and widely distributed in the islands are _Sorex vagrans_, _Peromyscus maniculatus_ and _Microtus townsendii_. These species, at least, probably reached the islands at an early time. The two last named are now subspecifically distinct from their mainland relatives. Other mammals which probably were established before the arrival of the white man include the mink, otter, beaver, muskrat, raccoon and black-tailed deer.

The Great Basin Fauna of eastern Washington exists as three units, one on the Columbian Plateau, another in southeastern Washington and the third in the Yakima Valley area. The desert species of the Yakima Valley are more closely related to the species of eastern Oregon than they are to those of the Columbian Plateau. In a number of respects the Columbian Plateau gives indications of age. The ground squirrel, _Citellus washingtoni_, is related to, but specifically distinct from _Citellus townsendii_ of the Yakima Valley and eastern Oregon. _Perognathus parvus lordi_ is a well-marked race, as is _Microtus pennsylvanicus kincaidi_ and _Thomomys talpoides devexus_. We suppose that these species were present on the Columbian Plateau at least through the Recent and probably through all of Wisconsin Time. The loess deposits of eastern Washington seem to have been laid down in Wisconsin and Recent times. These indicate an arid climate which, although probably cool, was probably not so cold as to exterminate these species. On the other hand, some species that are now abundant on the Columbian Plateau seem to have arrived there relatively recently. The black-tailed jack rabbit, for example, was unknown in eastern Washington before 1870 when it appeared in Walla Walla County. In 1905 it crossed the Snake River on ice and invaded the Columbian Plateau where it rapidly spread over the whole area. In January, 1920, it crossed the Columbia in two places and spread over the Yakima Valley.