1914] 
Jackson: Land Vertebrates of Ridgeway Bog 
45 
occurrence in Iowa bogs and swamps, and consequently in the 
state of Iowa, of such characteristic bog plants as Sphagnum, 
Larix laricina, Picea mariana, Sarracenia purpurea, Leduin groeyi- 
landicum, Kalmia glauca, Chamaedaphne calyculata, Vaccinium 
canadense, and Oxycoccus oxycoccus (cf. Pammel, 1909). Un- 
fortunately the fauna of Iowa bogs is imperfectly known. 
In absence of proof to the contrary, it seems best to conclude 
for the present, therefore, that the typical bog biota existed dur- 
ing the Glacial Epoch principally at the edge of the ice sheet and 
upon the debris covering the ice sheet itself. The ice at the border 
of the glacier was probably relatively thin and broken, and there 
is no reason to doubt that its surface supported plant and animal 
life. Unfortunately there has been no ecological study of the biota 
of a modern glacier; such a study is greatly needed and might help 
to enlighten us upon possible biotic conditions during the Glacial 
Epoch. That life can exist and thrive on a glacier is evident from 
the observations of Russel upon Malaspina Glacier, Alaska. 
Russel writes: “The forest covering the greater portion of the low- 
lands extends up over the moraine-covered bluff of ice and thence 
inland on the surface of the glacier for 4 or 5 miles. The face 
of the ice bluff is so completely covered with boulders, earth, and 
vegetation, that it is seldom one has so much as a glimpse of the 
ice beneath. In fact, an unobserving person might wander over 
it for hours without noticing that there are occasional ice out- 
crops’’ (Russel, 1893, p. 19). “The vegetation on the surface of 
Malaspina glacier, where we approached it, had no breaks or open- 
ings through which we could travel northward, but was so dense 
that we could not possibly force our way through it when encum- 
bered with packs. We decided, therefore, before attempting to 
proceed, to cut a trail through the forest to reach the barren mo- 
raine to the north” (Russel, 1893, p. 20). “The vegetation 
through which we cut a trail consisted principally of alders, growing 
to a height of 20 or 30 feet, but on the outer or older portion of 
the moraine there are dense groves of spruces, some of which are 
3 feet in diameter. The spruce trees decrease in number and be- 
come of smaller size toward the interior. Besides these there is an 
occasional cottonwood and a dense undergrowth of salmonberry 
and huckleberry bushes, devil’s club, and rank ferns, mostly of the 
genus Asplenium, in great profusion” (Russel, 1893, p. 21). “In 
