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INVESTIGATIONS IN MINNESOTA AND NORTH DAKOTA. 349 
‘the south has suffered more from erosion, deep ravines and waterways 
having been cut through the drift, and in places touch bedrock. Big 
‘Stone Lake is from 35 to 38 miles long and from 14 to 2 miles wide. 
The lake lies in more curves than Traverse and is less regular in width. 
It exceeds Lake Traverse in depth, its maximum depth being 35 feet. The 
bottom is of sand, and in some places a few inches of mud, strewn with 
bowlders of various sizes. The temperature of the water at surface and 
bottom is practically the same, owing to the frequent winds that stir 
the water to the bottom. This body of water is subject to less fluctua- 
tion in depth than Lake Traverse, on account of the outlet, which the 
latter does not possess. 
The water contains but little mineral matter and is always clear and 
fresh. The lake is said to be supplied with water from large springs in 
the bottom, but nothing of the kind was observed, though several fine 
springs along the eastern shore were visited. Besides the springs and 
the direct surface drainage from a comparatively small area, the lake 
receives the inflow from Little Minnesota River. The banks, which for 
the most part are of the same slope and are almost continuous with the 
higher hills, are composed entirely of drift material, no outcrop oceur- 
ring except at the foot of the lake. The shore is skirted with a narrow 
belt of small timber that offers protection and shade. There is very 
little vegetation in the water. Around the inlet and outlet are a few 
acres of rushes, and these are bordered by a small area of submerged 
vegetation. 
The lake is covered with ice during the winter, though it never 
freezes to the bottom. Fish food, such as water insects, larvee, crusta- 
ceans, and mollusks, is not as abundant as in Lake Traverse, yet the 
supply is apparently sufficient. Two species of water-snail are common, 
and a few shells of Anodonta were observed. It was also reported that 
these bivalves were numerous about certain islands in the lake. 
Theyoung of Catostomus teres and Moxostoma macrolepidotum, together 
with Percopsis guttatus and a few species of Htheostoma and Notropis, 
were also common. 
The lake is well stocked with several varieties of good food-fishes, 
foremost among which are pickerel (Lucius luctus), bass (Mieropterus sal- 
moides), wall-eyed pike (Stizostedion vitreum), rock bass (Ambloplites 
rupestris), and crappie (Pomoxis sparoides). 
The pickerel is one of the most abundant species; specimens weighing 
from 8 to 12 pounds are often obtained. It is easily taken with the hook, 
almost anything that will satisfy its voracious appetite or attract its 
attention serving for bait. The large-mouth black bass is the favorite 
of the angler, since much more skill is required in its capture. Almost 
any bait will suffice to take this species here, but the young of Car- 
piodes velifer, 14 to 2 inches long, and Fundulus diaphanus, of about the 
same size, are found most frequently in bait buckets, while the smaller 
species of Pimephales and Htheostoma are not infrequently used. 
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