12 THE AMERICAN MIDLAND NATURALIST 
represent the relative abundance of that species in the area. 
An asterisk, (*), indicates that the species was found to be 
less than 1 per cent in the area and locality involved. A 
blank space opposite the name of a species indicates that 
living shells were not collected in either the area or the lo- 
calities of it. 
AREA I. 
Boundaries; lower half of Diamond Island, Miss. R. to Red 
Wing, Minn., at High Bridge. Status, subject to fishery. 
Length in Linear Miles, 4.2. Physical Conditions, estimated 
7-8 ft. high water. Current about 5 miles per hour. Bottom 
mostly gravel and sand. Middle sections of area infested 
with snags. 
LOCALITIES REPORTED UPON. (ref. maps.) 
I—1. Starting point of drags Govt. Day Mark 958-n near 
center of Diamond Island, 25 ft. from shore on Minnesota 
_ side of channel. July 7, 1920. 
 J—2. Starting point of drags Govt. Day Mark 958-k, 
(above island 23), Wisconsin side of channel, 30 ft. from 
shore, about 14 mile down stream from preceding locality. 
I—6. Starting point of drags, 3800 ft. upstream from 
Govt. Day Mark 958-g across the mouth of slough about 1 
mile above Red Wing on Minnesota side, 50 ft. from mouth . 
of slough. July 9, 1920. 
