HISTORICAL REVIEW 11 



molluscan shells abound. Nearly every exposure in the sandy district west of 

 the beach, from the main part of the city of Chicago southward to Englewood 

 exhibits them. This beach is, therefore, in striking contrast with the two 

 higher beaches, which contain few remains of aquatic life. 



"An excellent artificial section across this beach, made by the Fullerton 

 avenue conduit, which leads from the Chicago River eastward to Lake Michi- 

 gan, across the north part of Chicago, is discussed above. The deposit through- 

 out is mainly sand, but some gravel is encountered. Shells of Unios and other 

 mollusks were noted at frequent intervals throughout nearly the whole width 

 of the deposit. Beneath these beach deposits there is everywhere a pebbly 

 blue-gray clay, apparently an unmodified glacial till. Some of the sewer ditches 

 in Hyde Park, west of Grand boulevard, have reached peat deposits below sand, 

 at a level a few feet above the lake. Wood has often been found in the sand 

 west of this beach in Chicago. " 



The sections mentioned above contain strata referable not alone to the 

 Toleston stage, but to the previous stage, as already noted. The peat deposits 

 in Hyde Park are evidently referable to the Post-Glenwood or Bowmanville 

 stage. 



1897. blatchley. 16 — Mr. W. S. Blatchley in discussing the geology of 

 Lake County, mentions glacial Lake Chicago. On page 38 silts and marly 

 clays are mentioned but no organic remains are recorded. On page 89 the 

 presence of the mammoth and mastodon are noted. 



1898. baker. 17 — Mr. Frank C. Baker mentions the following species as 

 occuring in postglacial deposits: 



Quadrida trigone. Corner Wrightwood Avenue and North Clark Street. 

 Quadrula undulata. Corner Frederick and North Clark streets. 

 Quadrida species. Hall Street. 



These three species were found in excavations for buildings. 



Plenrocera elevatum. Corner Sheffield and Lincoln avenues. 

 Goniobasis livescens. Corner Sheffield and Lincoln avenues. 

 Goniobasis livescens. Balmoral Avenue north of Bowmanville. 



At Willow Springs, in the river bank, the following species were found: 



A nodonta grandis Planorbis trivolvis 



Unto gibbosus Physa ancillaria warreniana 



Quadrida rubiginosa Amnicola limosa 



Spkaerium simile Amnicola emarginata 

 Sphaerium stamineum 



The additional species mentioned in this paper belong to the deposits of 

 the recent stage. It is impossible to correlate these fossils with any one of the 



16 An. Rep. Geol. and Nat. Res. Ind. XXII. 



17 Bull. Nat. Hist. Surv., Chi. Acad. Sci., Ill, part I, p. 23.. 



