SHIRAS EXPEDITIONS TO WHITEFISH POINT. 127 



abundantly represented. This marsh is the only place in the White- 

 fish Point region where horned dace were found in any num])ers. 

 The marsh appears to ])e an im])ortant feeding ground for the smaller 

 fish. 



The marginal shoals (No. 3, above) M^ere visited by many small fish, 

 but a representative collection of them was not made; one species, the 

 barred killifish, seemed to be confined to these places and was tolerably 

 common. 



The i)()()l Ix^low the beaver dam (No. 4, above) was frequented by 

 brook sticklebacks, red-bellied dace, Lnicisciis neogaeus, black-nosed 

 dace, and mud minnows. 



The stickk^backs were numerous, and ai)peared to thri\e better than 

 in any habitat examined in the Whit(>fish Point region. Some of 

 them were large, being nearly, three inches long. A few opened had 

 been eating insects and algae. The other fish were all small and present 

 only in small numbers. 



Marsh Lakes and Streams. 



The small lakes among the sand ridges on the strip of lowland along 

 Lake Superior with their outlet streams, channels, pools, l)eaver runs, 

 and other bodies of water connected with them, contain many small 

 fish and some large ones. They are, moreover, everything considered, 

 the most productive places for studying and collecting acjuatic organisms 

 in the Whitefish Point region. The lakes given particular attention 

 are close to Vermilion and are shown on the sketch map. The names 

 used for these were for the most part invented by the writer. 



According to Leverett (1911), regions below the Nipissing shore line, 

 including the lowland about Vermilion, are very young geologicall}", 

 perhaps not older than three thousand years. When the waters of the 

 Great Lakes descended to their present level, sand ridges, produced 

 probably by both waves and ice, were formed with the intervening de- 

 ])ressions. Marsh plants began to grow and thrive here till they cap- 

 tured the shallower parts of the flooded low ground. In places, the beavers 

 made dams to retain and elevate the Avater, which on rising drowned 

 out portions of the marsh or otherwise changed its features. These 

 animals thus helped to preserve the small lakes, and in this and 

 other ways they have been a dynamic factor in determining th(^ char- 

 acter of the fish habitats. Man has also affected the region in a similar 

 way by damming the water to facihtate cranberry culture. No inlets 

 were found leading to these lakes, except short streamlets from springs 

 near the base of the Nipissing l)luff. They ai^pear to be fed chiefiy 

 by seepage from the higher ground. The bottom of the.se lakes is at 

 foundation a hard, yellow sand, but over this in many places, there is 



