BOTANICAL SURVEY OF THE HURON RIVER VALLEY. 
Il. A PEAT BOG AND MORAINAL LAKE.* 
Lewis H: WELD. 
(WITH SIX FIGURES ) 
WHILE the general history of morainal lakes and the super- 
ficial relations of their plant societies have long been familiar both 
to botanists and geologists, there has been great lack of detailed 
‘information regarding changes now taking place and the effects 
of such changes onthe distribution of plants and consequent 
vegetable accumulations. In fact, anything approaching a satis- 
factory comparative study, based on reasonably complete data, 
has thus far been out of the question. The evidence goes to 
show that the rate at which morainal lakes in southern Michigan 
are filling up has been extremely variable and that oscillations of © 
water level and various other changes are in progress, directly 
affecting biological conditions. For future critical studies, there- 
fore, it is essential that definite observations of present conditions 
should be permanently recorded. The large number of morainal 
lakes in the Huron River Valley and the numerous peat bogs 
accompanying them, some of which are reported to be as much 
as forty feet in thickness, offer excellent opportunity for scien- 
tific exploration and commercial enterprise to cooperate with 
mutual advantage. 
The lake, or pond, which forms the subject of the present 
study, is the first and smallest of the so-called Three Sister Lakes, 
and lies three miles west of Ann Arbor, just south of the trolley 
line. It is oval, or ovate, in outline, with the long axis SSW 
by NNE, the larger end lying towards the south. Its great- 
est length is 600" (180™) and its width 400* (120™); on the west 
«This work, to which Mr. Weld gave a large part of his time for a year, was incom- 
plete when he left the University of Michigan in July 1902. 
fully done, it seems desirable to place his observations on record. With his approval, 
some necessary changes and additions have been made by V. M. Spalding, under 
whose direction the survey is in progress. 
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38. [JANUARY 
