126 LIFE OF THE PLEISTOCENE 



Mr. J. L. Tunison, of the Page Engineering Co., Chicago, has brot to 

 the writer's attention an interesting deposit situated one mile from Cary, 

 McHenry Co., near the Fox River. The section shows the strata indicated 

 in the table below: 



1. Black loam 2Y 2 feet 



2. Brown earth iy 2 " 



3. Marl 4 



4. Moss 2 " 



5. Marl 2 



The two marl beds and the moss bed contain the remains of life. Stratum 

 3, the first marl, contains six species of mollusks, as noted below: 



Vahata tricarinata Amnicola lustrica 



Valvata lewisii Planorbis parvus 



A mnicola limosa Planorbis exacuous 



The moss bed, stratum 4, is an almost solid mass of vegetable matter. 

 Dr. E. W. Berry, of Johns Hopkins University, examined some of the material 

 and reported as follows: "The moss layer between two layers of marl is cer- 

 tainly very interesting, illustrating as it does changes of level. The form 

 is a sub-species of Plagiothecum denticulattim (Linne) B. & S., probably near 

 the subspecies rosaceum (Hampe) B. & S. This moss is very common and wide- 

 spread in middle latitudes and may possibly be a composite form. It grows in 

 various moist (not necessarily swamp) situations from the Atlantic to the Paci- 

 fic." 



The marl beneath the moss, stratum 5, contained but one species of mollusk, 

 Galba galbana, a species characteristic of the colder period following the retreat 

 of the ice sheet. The cause of the changes of level in the body of water in which 

 these animals and plants lived is not at present known. 



a. Lake Kankakee 



Leverett 23 and others have shown that a lake once occupied a large part of 

 the Kankakee marsh area, and Bradley, 24 a number of years ago, reported 

 species of Unio and Paludina ( = Campeloma) from sand banks along the 

 Iroquois River, 15-30 feet high, which he believed were made by an old lake. 

 This lake is believed to have been very shallow and there is no reason to doubt 

 the possibility of a biota migrating up the Illinois River and occupying this 

 old lake basin, even while the ice was not many miles away. A careful study 

 of this basin would no doubt reveal many evidences of Pleistocene life. 



23 Illinois Glacial Lobe, pp. 328-338, plate VI. 



24 Geol. 111., IV, p. 227. 



