INTRODUCTION. 5 



voles and long-tailed shrews of various species, northern jumping mice 

 * * * white-throated sparrow, Blackburnian and yellow-rumped warblers, 

 olive-backed thrush, three-toed woodpeckers, spruce grouse, crossbills, and 

 Canada jays. Counting from the north this zone is the first of any agri- 

 cultural importance. Wild berries — as currants, huckleberries, blackberries 

 and cranberries — grow in profusion, and the beechnut (in the east) is an 

 important food of the native birds and mammals. (Ibid. pp. 19-20.) 



"The Transition zone is the transcontinental belt in which Boreal and 

 Austral elements overlap * * The zone as a whole is characterized by 

 comparatively few distinctive animals and plants, but rather by the occur- 

 rence together of southern species which here find their northern limit and 

 northern species which here find their southern limit. It may be sub-divided 

 into three faunal areas * * * The eastern humid or Alleghanian area 

 comprises the greater part of New England, southeastern Ontario, New 

 York, Pennsylvania, Michigan, Wisconsin, Minnesota, eastern North Dakota, 

 northeastern South Dakota, and the Alleghanies from Pennsylvania to 

 Georgia. * * * In the Alleghanian faunal area the chestnut, walnut, 

 oaks and hickories of the South meet and overlap the beech, birch, hemlock 

 and sugar maple of the North; the Southern mole and cotton-tail rabbit 

 meet the Northern star-nosed and Brewer's moles and varying hare, and 

 the Southern bobwhite, Baltimore oriole, bluebird, catbird, chewink, thrasher 

 and wood thrush live in or near the haunts of the bobolink, solitary vireo, 

 and the hermit and Wilson's thrushes. Several native nuts, of which the 

 beechnut, butternut, chestnut, hazelnut, hickory nut and walnut are most 

 important, grow wdld in this belt. Of these the chestnut, hickory nut and 

 walnut come in from the South (Carolinian area) and do not extend much 

 beyond the southern or warmer parts of the Alleghanian area." (Ibid. pp. 

 20-21). 



Dr. Merriam's map accompanying the paper just cited assigns the entire 

 Upper Peninsula of Michigan to the Canadian zone, together with all that 

 part of the Lower Peninsula lying north and east of a line drawn from Traverse 

 City on Great Traverse Bay to Point Au Gres at the mouth of Saginaw Bay 

 on Lake Huron. The Carohnian zone includes the two southernmost tiers 

 of counties in the Lower Peninsula and all those counties bordering Lake 

 Michigan on the east as far north as Great Traverse Bay (20 counties in all). 

 The remainder of the Lower Peninsula, covering about 30 counties, is assigned 

 to the Transition zone. This arrangement gives about tw^o-fifths of the 

 state to the Canadian, two-fifths to the Transition or Alleghanian, and one- 

 fifth to the Carolinian, an apportionment to which we cannot entirely 

 agree. In our opinion little or no error would be made if the entire state, 

 Upper Peninsula as well as Lower, were assigned to the Transition. With 

 the possible exception of Isle Royal and Keweenaw Point no part of the state 

 sustains a purely Boreal (or Canadian) fauna or flora, and it seems equally 

 certain from the data at hand that even the southernmost counties are not 

 purely Carolinian. 



Of course since the Transition is characterized by the mingling of the 

 forms belonging to the two zones lying on either side, it becomes necessary 

 to draw two dividing lines instead of one. Near the southern boundary of 

 the Transition Carolinian forms should predominate, while near the northern 

 boundary Canadian forms should prevail. At first sight it would seem 

 perfectly simple to formulate a rule by which the boundaries of the Transition 

 might be surely defined. INIoving southward in the Canadian zone that 

 spot in which the first Carolinian species is encountered would give one point 



