THE LIFE OF GLACIAL LAKE CHICAGO 85 



cutting down of the outlet during the subsequent rise of the water which 

 initiated the Calumet stage. The presence of Elliptio crassidens and Pleuro- 

 bema coccineum magnalacustris is to be noted. 



Elliptio crassidens Campeloma integrum 



" gibbosus " integrum obesum 



Pleurobema coccineum magnalacustris Goniobasis livescens depygis 



Crenodonta undidata Valvata tricarinata 



Fusconaja undata Amnicola limosa 



Eurynia recta « " lustrica 



Lampsilis ventricosa Physa warreniana 



Pisidium virginicum Planorbis deflectus 



At a point where Austin Avenue crosses the Ogden ditch a silt bed 

 was observed which contained: 



Fusconaja rubiginosa Pleurobema coccineum magnalacustris 



Rotundaria tuberculata Elliptio gibbosus 



Eurynia recta 



In the above lists Goniobasis livescens depygis and Fusconaja solida are not 

 found in the deposits of the north shore channel. 



iii. Vertebrate Life 



Birds 



The biota of this stage included vertebrates as well as invertebrates and 

 plants. In a deposit of silt between two beds of naiads the humerus of a ^C 

 Merganser (Mergus serrator) was found. It was identified by Dr. R. W. Shu- 

 feldt. 



Mammals 



The remains of the higher vertebrate animals have been found in the 

 Chicago area, some of which may be referred to this stage of the lake history. 

 Many records are from strata which cannot be definitely correlated, but as it 

 is believed that these animals roamed the shores of the ancient lakes until a 

 late period, they are all here included. 



Mammut americanum 



v 

 Wicker Park, near Milwaukee Avenue, covered by 13 feet of silt. Jaw, teeth, and other 



bones 49 



Middle beach, Evanston, on C. & N. W. Railroad. Fossil ivory 49 



Lake County, Indiana 50 



Berrien County, Michigan 51 



50 Blatchley, 1897, p. 89. 

 "Walker, Nautilus, XI, p. 121. 



