SANGAMON INTERGLACIAL STAGE. 293 



It is this soil which attracted the attention of Orton in his examination 

 of wells near Marshall, in Highland County, Ohio,^ but the soil there is 

 within the limits of the Wisconsin drift. It is probable that the deposits of 

 peat below the Wisconsin drift near Germantown, in Montgomery County, 

 Ohio, also brought to notice by Orton,^ are referable to the Sangamon. In 

 fact, the great majority of buried soils reported in Ohio, Indiana, and Illinois 

 appear to be at this horizon. The soil attracts attention more effectively 

 when found at considerable depth than in places where it is covered by 

 only a few feet of silt. One often passes it in the latter situations without 

 realizing that it is really at a lower horizon than the surface soil, for the 

 surface soil is liable to be washed down the slope below the IcA'el of the 

 Sangamon soil. A careful inspection, however, will place beyond question 

 the frequent occurrence of the Sangamon soil. In many cases it can be 

 traced back along ditches until it passes beneath the surface silt, but where 

 this can not be done an examination of the constitution of the Sangamon 

 soil will reveal the presence of pebbles, which distinguish it from the 

 pebbleless siu-face soil. 



The Sangamon soil, in the region under discussion, does not commonly 

 show a black color, though exposures of such a color are met with in all 

 parts of the region. The evidence of a land surface is more generally 

 found in the deep-brown color and weathering or soil-producing disintegra- 

 tion of the upper part of the till. The deep brown changes gradually below 

 to the ordinary yellow color of oxidized till, but at top it terminates abruptly 

 at the base of the overlying silt. The color of the silt being much lighter 

 than that of this brown soil, the contrast is very marked. The deep-brown 

 color extends usually to a depth of 2 feet or more, while leaching and 

 discoloration are noticeable to 6 or 8 feet. The amount of discoloration is 

 somewhat greater than is commonly found at the surface of the Wisconsin 

 drift, and numerous comparisons of the Sangamon soil with the post- 

 Wisconsin soil lead to the opinion that the Sangamon involved more time 

 than has elapsed since the culmination of the Wisconsin stage of glaciation. 

 The same opinion is reached upon comparing- the amount of leaching. On 

 the lUinoian drift it is rare to get a response with acid within 6 to 8 feet of 



1 Rept. Geol. Survey Ohio, 1870, p. 266. 



' Am. Jour. Sci. , 2d series, Vol. L, 1870, pp. 54-57, 293. See also Kept. Geol. Survey Ohio, 1869, ] .p. 

 165-169. 



