1904 | WELD: BOTANICAL SURVEY OF HURON VALLEY 39 
small lakes of Michigan. They lie on the western slope of the 
‘terminal moraine which was formed by the Erie lobe of the ice 
sheet, and which now extends northeast and southwest across 
the county. Just south of the second and third lakes is a high 
kame, and these lakes lie in some of those local depressions in 
the drift which are characteristic of a kame area. The present 
outlets follow the glacial drainage channels. These flowed away 
from the ice front to the north and northwest to the Huron 
River, which at that time had just formed in the re-entrant angle 
between the Erie and Saginaw lobes and flowed to the west 
through the Portage and Grand into Lake Michigan. All the 
region east of this terminal moraine, including Ann Arbor, was 
then occupied by the ice sheet, and the glacial drainage was to. 
the west. 
As is well known, such morainal lakes are destined sooner 
or later to become obliterated by the combined action of erosion 
and vegetation. The process goes on more slowly in some than 
in others, depending on size, depth, character of the shores, 
direction of winds, and the nature of the vegetation which gets 
a foothold. The first lake represents a fairly advanced stage in 
the process, the second and third occupying a far larger propor- 
tion of their original basins. 
The characteristic zonal distribution of the vegetation is well 
marked in all three of these basins, especially in those of the 
first and third, the lake lying in the center with water lilies 
around its margin, then sedge and sphagnum, cassandra and 
other shrubs, and finally forest. It is noteworthy that the lake, 
as in many similar cases, is nearer the eastern than the western 
side of its basin, the bog and forest being better developed on 
the western side. This is not so evident in younger stages, but 
is very noticeable at the first lake. 
Proceeding now to a more detailed account of the vegetation 
of the first lake, we may conveniently follow the zones in their 
natural order: 
1. Potamogeton zone.—This is represented by VPotamogeton 
lucens? in deep water, at the outer edge of the pond lilies, not at 
?The nomenclature is that of Gray’s Manual. 
