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 wild 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 Carolinian 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 two-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. Moving southward in the Canadian zone that 
spot in which the first Carolinian species is encountered would give one point 
