1903] TRANSEAU—BOGS OF THE HURON RIVER VALLEY 373 
alteration... They were originally strongly cuticularized, and this has 
aided in their preservation. The color is commonly a pale yellowish- 
brown. During life these plant materials become strongly matted 
and interwoven, and this structure frequently persists. It is this 
structure that gives to the Carex-Eriophorum zone in many lakes its 
strength to support heavy bodies. A man’s weight will carry the 
substratum a foot beneath the surface of the water, but it seldom 
breaks under the strain. In the case of lakes where this zone is 
unusually developed, it may cover a large part of the lake surface and 
be of great importance in the filling in of peat: - In such cases the 
deposition takes place largely by the gradual falling of material from 
the under side of the floating substratum. On account of the slight 
weight of the material, it does not descend and produce a compact 
deposit on the bottom, but forms a sort of thick liquid peat. 
The sphagnum-shrub zone, where well developed, usually shows a 
brown peat beneath it. It is composed largely of sphagnum and the 
semi-decayed twigs, rhizomes, and leaves of the other plants. It is 
distinctly fibrous, but of a type different from that of the sedge zone; 
the fibers are short, and the material is not nearly so tenacious. 
Under the tamaracks a large part of the annual peat increment is 
made up of the tamarack needles, though mosses (Hypnum, Sphag- 
hum, and Polytrichum) usually are of importance in this connection. 
The color is reddish-brown and darker than that of the shrubby 
zone. The fibrous structure is still less apparent, though present. 
When these bogs have been burned over and partially drained, 
there frequently comes in a dense ground covering of moss (Poly- 
itichum). In such cases the peat continues to accumulate, largely 
through the agency of this plant. In such situations the peat 1s a 
teddish-brown, and the plant structures have practically disappeared 
through decay. Below the upper layer, the peat when moist has the 
sticky, clayey properties of well-decomposed peat. 
ne other well-marked stage is shown in the areas of muck land 
Pa: under cultivation to onions and celery. Under the influence of 
drainage and tillage, the disintegration is nearly complete. All plant 
Structures have disappeared, the humous acids have been largely 
neutralized or washed out, and there is left only a fine, powdery, 
brownish-black “muck.” 
