106 



Notice was given of opportunity to visit the Mine Rescue 

 Station. 



F. C. Baker presented a paper which is given in abstract 

 below : 



THE ECOLOGY OF THE SKOKIE MARSH AREA WITH 

 SPECIAL REFERENCE TO THE MOLLUSCA. 



The present paper is an attempt to place on record a minute 

 study of a small territory with special reference to its mollus- 

 can inhabitants. The area chosen is in the Skokie Marsh 

 Region north of Chicago. The territory actually surveyed in- 

 cluded a tract of land three miles long and one mile wide, ex- 

 tending from Glencoe west to Shermerville. It is situated in 

 the Glacial Skokie Bay, which, by natural drainage, has be- 

 come a swamp of large extent. Three streams traverse the 

 area in a southerly direction : ( 1 ) a small stream through the 

 center of the marsh near Glencoe, which is for the most part of 

 a transient character; (2) the east branch of the Chicago 

 river; and (3), the north branch of the Chicago river, flow- 

 ing through Shermerville. This area divides into five subordi- 

 nate areas : A, the marsh, \\<hich is low and wet with the 

 characteristic Typha and Calamagrostis plants ; B, an interme- 

 diate ridge west of the marsh, which is low and wet on its 

 eastern edge, but which rises to a height of twenty feet above 

 the Skokie stream on its western edge ; this region contains 

 several forested areas of oak, cottonwood, maple, elm, and other 

 large trees ; C, the east branch of the Oiicago river which 

 embraces a wide flood plain bordered by rather high terraced 

 banks, and supporting a characteristic swamp and bog vegeta- 

 tion, notable among which is the button-bush ; D, a large area 

 west of the east branch, which rises to a height of forty feet 

 above the river and is heavily forested with large trees of elm, 

 oak, cottonwood, maple, etc. ; E, the north branch of the Chi- 

 cago river, which flows through a flat, more or less marshy 

 plain. 



Each of the above five areas is divisible into several stations,. 



