The Relation of Mollusks to Fish in. Oneida Lake 35 
consin) doubtless modified the original topography, scooping 
up the soft shale and redepositing it in the form of moraines 
and drumlins. As the roek (Clinton shale) is but 14 feet 
below the surface at Brewerton, the outlet for such a hypo- 
thetical river must have been in some other direction, per- 
haps through Big Bay. The west end of the lake is very 
shallow, indicating a large amount of glacial filling, if a river 
ever flowed in this direction. 
Oneida Lake is physically better adapted for maintaining 
a large and varied fish fauna than either Cayuga or Seneca 
Lakes because of its shallowness, especially about its borders, 
where feeding and breeding grounds are extensive. The 
Finger Lakes, on the other hand, have little shallow water, 
excepting at the ends, hence cannot support much vegetation 
upon which animals depend, in the ultimate analysis, for 
food. 
