252 
Harvey Stallard 
square yards up to a few square rods. In the spring these bogs 
are covered with water varying in depth from eighteen inches to 
four or five feet. Later in the summer on account of evaporation 
and drainage the water Jevel falls to such an extent that the surface 
of the bog becomes firm. From such evidences as fire scars on 
the stumps around the edge of the bogs and on some of the 
remaining hummocks, it became apparent that fires had disturbed 
the vegetation and had initiated secondary succession which in the 
main has reached the Carex-Calamagrostis associes. 
Numerous other hogs in the vicinity of Hubert were visited 
and among these was found north of Hubert Lake in the centre of 
the N.W. \ of section 24 an atoll whose outer trench has been 
formed recently. The hog differs from the two mentioned above in 
that it has no outlet. In the spring, when the water-level is high, 
the centre is occupied by a small pond varying in depth from 
eighteen inches to three feet. The outer trench of water varies in 
width from a few feet to one or two rods, and in depth from one to 
three feet. On the south-west side the trench has not been formed, 
and here the Sphagnum with the heaths join directly with the 
vegetation of the bank. The vegetation of the central pond is 
composed largely of Carices, Nymphcea, and other plants character¬ 
istic of the Carex-Nymphcea associes. On the sphagnum areas are 
to be found the usual species of Vactinium, Chamcedaphne, Ledum, 
Andromeda, Eriophorum, Comarum and Menyanthes. The vegeta¬ 
tion in the outer trench consists of species of Carex, Calamagrostis 
and the subdominants which are generally found in the Carex- 
Calamagrostis associes. The banks are sparsely covered by jack 
pines, underneath which is a mat of Arctostaphylos and Vaccinium. 
The total area of the bog is about twenty-five acres, its 
average width and length being respectively about fifty rods by 
eighty. The banks of the north and west sides rise gradually to 
perhaps twenty or thirty feet. On the east they rise not higher 
than ten or fifteen feet. By means of the peat-sampler the depth 
of the centre was found to be about twenty-two feet. 
A third very characteristic atoll is located near the Wild 
Flower Garden in Glenwood Park of Minneapolis. This bog is 
narrow and long. It is surrounded on three sides by high banks 
which rise rapidly and reach a maximum height of perhaps fifty 
feet. The north bank is lower but does not afford an outlet. The 
vegetation of the banks consists of a bur oak and red oak grove 
with a mat of blue grass beneath. The soil is a sandy morainic 
