THE ILLLN01AN ICE INVASION 301 



The mastodon mentioned by Udden 83 as being found in a gravel pit (Adam 

 Saal's) between Dead Lake and the river channel, a mile south of Pekin, in 

 sand, under gravel, is probably referable to the Sangamon interval. The 

 overlying gravel is said to be of Wisconsin age. 



The horse appears to have lived during the Sangamon interval as its remains 

 occur in strata referable to this horizon. 84 The maxillary bone with a few 

 teeth were found in a bog on the confines of Bond and Fayette counties. 85 

 The species was identified as Equus complicatus. Both the horse and the 

 bison {Bison latifrons) have been reported 86 from Illinois, the former from Greene 

 County and Alton, Madison County, and the latter from near Alton. The 

 horizon from which these specimens came is, however, indefinite. Bison lati- 

 frons 7 has also been reported from the Kaskaskia River, Moultrie County, in 

 dark clay and debris. Details are not given but the deposit is possibly Sanga- 

 mon, beneath Wisconsin till. Illinoian drift has been identified beneath 160 

 feet of Wisconsin till at Barrington, Lake County but no biotic material has 

 been recorded. 88 



3. INDIANA 



a. Old Soils 



In Indiana deposits referable to the Sangamon interval have been recorded 

 from several localities. In Delaware County 89 well diggers encounter a layer 

 of vegetable material at a depth of about 40 feet, composed of stumps and 

 trunks of trees, twigs, leaves, and vegetable mold. In Boone County 90 black 

 muck or loam, with branches of trees and other vegetable matter is reported 

 beneath the Wisconsin drift. In Ripley and Decatur counties 91 old soils have 

 been reported which should probably be referred to the Sangamon. At Sey- 

 mour, 92 Jackson County, an old flood plain of the White River is also probably 

 referable to this stage. The great majority of the buried soils reported in 

 Indiana, Illinois, and Ohio appear to belong to the Sangamon interval. 93 



At the edge of the Illinoian drift in Dearborn, Ohio, and Switzerland 

 counties several interesting sections have been exposed. 94 Well sections in 



88 Bull. 506, U. S. G. S., p. 61. 

 M Hay, Science, N. S., XXX, p. 891. 



"Leidy, Trans. Wagner Free Inst. Sci., II, p. 39; Gidley, Bull. Amer. Mus. N. H., 

 XIV, p. 91. 



m McAdams, Trans. St. Louis Acad. Sci., X, p. LXXX. 



" Broadhead, Amer. Nat., IV, pp. 61-62. 



"Leverett, HI. Glacial Lobe, p. 581. 



"Phinney, Geol. Ind., 11th An. Rep., p. 130. 



" Gorby, op. cit., 15th An. Rep., pp. 167-173. 



n Blatchley, op. cit., 29th An. Rep., pp. 431, 432. 



n Leverett, Mon. XLI, p. 263. 



93 Leverett, op. cit., p. 293. 



u Warder, Geol. Surv. Ind., 3-4 An. Rep., p. 404. 



