98 College of Forestry 
I have not extensive data on this point but im general I 
should say that in the Adirondacks submerged vegetation is 
generally sparse and especially limited to slight depths. In 
the larger lakes of this region the rocky shores and especially 
violent wave action operate to exclude almost wholly, 
anchored water vegetation. 
As to building up the substratum, the yearly addition of 
the season’s growth — for in my observation the heavy banks 
of pond weed die down to the imbedded parts or approx- 
imately so— results in a material addition to the organic 
sediment of the bottom although it should be noted that 
plants of this sort of habitat have only a minimum of firm 
tissues. The dead material is readily disintegrated and more 
or less thoroughly decomposed, resulting not in coarser or 
fibrous peat as that is popularly understood but in an oozy 
mass which gradually becomes compacted into the fine, black 
mud characteristic of those lake bottoms where the water is 
kept fresh and clear and well aerated. 
Submerged Aquatics and Marl Formation. 
Attention was called, p. 96, to the role of certain blue 
green algae in the deposition of calcium carbonate forma- 
tions. The formation of the numerous and rather extensive 
marl beds in lake bottoms and in swamp soils built up under 
water — Cicero Swamp, Montezuma Marsh, Tully Lakes, 
etc. — is ascribed now largely to water vegetation, in part to 
the blue-green algae as stated and particularly to Chara and 
in lesser degree to Potamogetons, ete. Discussion as to this 
matter will be found in Warming’s Ecolgy* pages 64 and 
65 and by Davis.” 
That material deposits of carbonate of lime are annually 
made by Chara and even Potamogetons is clearly shown in 
the case of Tully Lake. In one instance notably, heavy beds 
of Potamogeton were found in September to be so deeply 
lime incrusted as to be very brittle and fragile and the whole 
1 Warming (English translation), Ecological Plant Geography. 
2Davis, Chas. A. A contribution to the Natural History of Marl. 
Jour. Geo., 8:1900, pp. 485-497. 
