2 THE AMERICAN MIDLAND NATURALIST 
above it, resulting in a more rapid current in the former 
region, which is accelerated by the pressure of the impounded 
waters of the Lake. Where snags are abundant on the bot- 
tom, this current is strong enough to make mussel fishing with 
crowfoot bars somewhat dangerous. 
The bottom of the river within the areas is for the most 
part composed of fairly coarse gravel mixed with varying 
proportions of mud and sand. The latter increase perceptibly 
in the vicinity of the tributary streams of the region, the 
principal entering streams being the Cannon River at Red 
Wing, the Chippewa at Read’s Landing, the Zumbro near Wa- 
basha, Minn., and the Trempealeau below Winona, Minn. 
The Chippewa is principally responsible for the enormous 
quantities of sand brought into these areas discussed below 
Lake Pepin. Only through the construction of wing dams 
have the Government engineers been able to preserve a navi- 
gable channel. These dams are designed to catch the sand 
near mid-stream, deflecting it toward the shore where it 
ultimately forms sand bars or islands, but unfortunately 
smothering at the same time the valuable clam beds which 
formerly existed in the Mississippi below Lake Pepin, with 
the consequent discouragement of the clamming industry. In 
the opinion of some engineers, it appears practicable to ter- 
race the banks of the Chippewa near Lake Pepin in such a 
way as to divert the sand to fill up the low lying country near- 
by, but a better preventative would be the reforestation of 
the Chippewa drainage basin. The conservation of the 
national mussel resources in thus seen to be closely related 
-to other problems of national economy. 
Ill. STATUS OF THE MUSSEL FISHERIES IN 
RELATION TO THE PRECEDING. 
That stretch of the river about five miles northwest of Red 
Wing in the vicinity of Diamond Island, and which is known 
to old-time clammers as the Trenton Bed, is apparently but 
little worked, although our observations indicate that such 
might be profitably undertaken as it is in an area subject to 
fishery. At Red Wing itself the summer, of the survey, three 
clammers were observed. They reported that their returns 
seemed to be diminishing, although in past years this im- 
mediate section was considered one of the best on the river. 
