1914 ] 
Jackson: Land Vertebrates of Ridgeway Bog 
5 
cieties ran more or less parallel to Carp River. Succession was 
found to be much the same as in southern bogs, but the bog socie- 
ties were “not arranged in concentric zones;’’ he states further, 
however: “the sedge zone grades into a zone composed largely 
of Dwarf Cassandra^ . . . that is in turn followed by a society 
composed largely of Balsam Fir, Tamarack and White Spruce, the 
undergrowth of which consists principally of Dwarf Cornel, 
Creeping Snowberry, Labrador Tea, Pitcher Plant and Gold 
Thread on a thick carpet of Sphagnum and mosses” (Ruthven, 
1906, p. 34). Ruthven, however, does not distinctly associate 
the bog animals with the various plant societies within the bog 
area, nor does he point out ecological succession among the ani- 
mals of the bog, either per se or as associated with plant succes- 
sions. He considers that, “the fauna of these bogs is not charac- 
teristic;” mammals were represented therein by Hoy’s shrew, 
the red squirrel, and the red-backed mouse; the remaining verte- 
brates consisted of eleven species of birds — ^namely, purple finch, 
white-throated sparrow, magnolia warbler, cedar waxwing, red- 
breasted nuthatch, red crossbill, white-winged crossbill, olive- 
sided flycatcher, pine siskin, golden-crowned kinglet, and ruffed 
grouse. 
In this same publication Ruthven (l.c.) delineates the results 
of a preliminary ecological investigation of the fauna and flora 
of Isle Royale, Lake Superior, carried on during the summer of 
1904. These studies on Isle Royale were continued in more 
detail during the next summer (1905) and have been discussed 
in a compendious paper by Adams (Adams, and others, 1909). 
Several bogs were studied as a part of the general environment of 
the island; different stages of the lake-bog series were investi- 
gated from “the open lake without marginal vegetation,” “the 
partly open lake with marginal vegetation of varying width,” to 
“the wholly carpeted bog area” (Adams, and others, 1909, 
p. 218). Adams associates certain animals with the various plant 
societies in the bog, which he sums up in regard to the mammalian 
fauna as follows: “From the open water to the balsam-spruce 
forest there is a relatively simple change, from dominance of the 
aquatic and marsh types (supplemented by bats) to land forms 
which are terrestrial, as the weasels, terrestrial and arboreal, as 
Italics mine. 
