1914] 
Jackson: Land Vertebrates of Ridgeway Bog 
13 
C. By the settling of the ftuvio-glacial deposit itself (Leverett, vide 
Trarseau, 1905-1906, p. 361). This process often enhances the 
formation of depressions begun through causes A and B, and 
may in many cases form basins through its own action in areas 
left com.paratively level by the receding ice. 
In the region of the upper Wisconsin River are found depressions 
formed by each of the above mentioned processes. The topog- 
raphy indicates that the extremity of the ice lobe was in a very 
unstable condition; it appears as if a large section of the Chip- 
pewa Lobe, the lobe which covered this region, here disintegrated. 
Huge masses of ice separated from the main glacier and imbedded 
themselves in the drift, later to melt and form “kettleholes.’’ 
Other basins are long and shallow, and are sometimes drained by 
a creek or river; such basins were probably formed in most cases 
by unequal deposition of glacial debris during the retreat of the 
ice sheet. The banks of these elongated basins in this region 
are seldom high and steep, which indicates that the retreat of the 
ice sheet was here probably relatively rapid. Copious rains, and 
water from the melting ice, deposited the finer silt into depres- 
sions or carried it away through a drainage system then incom- 
pletely formed. Plant growth undoubtedly invaded many of these 
depressions and their banks before the main glacial lobe had 
entirely receded from the region, and especially would this happen 
in the shallower basins. The topography of the region today 
shows these depressions in various physiographical and ecological 
stages; open deep-water lakes, shallow lakes, sedge-grown swamps, 
heath-grown bogs, timbered bogs, and mesophytic forest may all be 
encountered within a comparatively small area. The Rhine- 
lander region, the region of Ridgeway Bog, lies in the older 
glaciation of this plateau. Here most of the lakes are shallow 
and many of them have been entirely obliterated by the action of 
erosion and vegetation; bogs are characteristic of the region. 
B. Climate 
The climate^ of this region is characterized by great annual and 
daily ranges in temperature, and by cold dry winters and moder- 
® Meteorological data herewith given are derived largely from the work of Day (1912, sections 
59 and 60); no data being available for Rhinelander, Wisconsin, an average is taken of the records 
for Crandon (12 years) and Prentice (11 years), Wisconsin, which lie at almost equal distances 
