18 LIFE OF THE PLEISTOCENE 



lake, showed one foot of peat about 5 feet above the lake, beneath the Toleston 

 gravels. Below the peat is a compact deposit of very fine gray sand of un- 

 known depth. A single shell was found in the sand close to the peaty layer. 

 A section studied by Leverett in 1888 showed similar peat layers, with asso- 

 ciated shell-bearing clays nine feet above the lake. Dr. Oliver Marcy, in 

 1864, made a record of an exceptionally good exposure in the cliffs, which were 

 then unprotected by the piers and artificial beach. The peat, a clay bed con- 

 taining molluscan shells of nine genera (all existing species) was found ten feet 

 above the lake. Farther down, on the contorted glacial clays, was found a 

 'humus soil, with stumps and log (coniferous),' six inches thick and buried by 

 three feet of gravel. A cellar excavation on Davis Street, Evanston, recently 

 showed a peat bed between the boulder clay and the over-lying Toleston gravels 

 and sands. Minute fibrous rootlets could be seen penetrating the till at the 

 base of the peat, indicating that the deposit is in situ, presumably a land sur- 

 face beposit. If so, it registers a stage of low water preceding the Toleston. 

 A marl bed near the Toleston gravels here, contains an abundance of shells." 



The deposits cited above probably belong to several stages and should not 

 all be referred to the Toleston episode. 



1910-1912. baker. 28 — The papers of this author outline the postglacial 

 life of the Chicago region substantially as presented in the present work. 



1912. hay. 29 — In this paper Hay discusses the Pleistocene Period and it' 

 vertebrates and incidentally refers to a skeleton of Amia calva from the bed ol 

 Lake Chicago and the presence of the mastodon and mammoth in parts of 

 Cook County, Illinois, and Lake and Porter counties, Indiana. 



1914. peattie. 30 — In this paper reference is made, incidentally, to peat 

 deposits and other evidences of life. Some of these may be interglacial. It is 

 evident that much valuable information has been available from these well- 

 boring and excavation records which has not been made to bear more directly 

 on these problems of Pleistocene life distribution because the material has not 

 been examined by those trained to interpret such data. 



1915. leverett 31 comments as follows on the peaty deposits found at 

 Evanston and Bowmanville: "Deposits of peaty material found under portions 

 of the Calumet beach have been interpreted to signify that the lake level stood 

 lower than the Calumet beach at a time prior to the development of that beach. 

 A conspicuous burial of peat under the gravel of the Calumet stage of the lake 

 is found in Evanston, 111., where the gravel extended southward as a bar into a 

 bay that stood back of the present city. A recent exposure of peat below the 

 Calumet beach at Bowmanville is noted by F. C. Baker. However, although 



28 Science, n.s., XXXI, pp. 715-717, 1910; Trans. 111. Acad. Sci., IV, pp. 108-116, 1912 



29 36th An. Rep. Dept. Geol. & Nat. Res. Ind., pp. 552, 710; 700-750, 1912. 



30 Journ. Western Soc. Eng., XIX, pp. 590-611, 1914. 

 « Mon. 53, U. S. Geol. Surv., p. 356, 1915. 



