80 PLEISTOCENE OF INDIANA AND MICHIGAN. 



Mr. Frank Galbraitli, an intelligent observer, who has dug 11 wells in the west part of Clay Township, reports the suc- 

 cession to be: Soil, yellow clay and gravel, black soil frequently with buried timber, and blue clay. Mr. Enos Wood- 

 ruff, in sinking two wells in the nortb part of Jackson Township, reports the same strata. Mr. James Bannister, of 

 Alert, has dug four wells and found the black soil in all and timber in part of them. Buried timber is generally found 

 in sinking wells about Newburg, on Sand Creek, and in the vicinity of Clarksburg. The finding of buried timber 

 several feet below the surface is a phenomenon so striking to the average mind that inquiry develops the fact in all 

 neighborhoods where the yellow clay is not replaced by sand or gravel, and frequent as the finding of timber may be, 

 it is not nearly so often noted as the more frequent occurrence of the black soil. In thickness it ranges from 2 to 8 feet, 

 most usually about 2 feet. In physical appearance it more nearly resembles the blue bowlder clay, and where it has 

 apparently been disturbed at some time in its history it is mixed with gravel. Its depth below the surface ranges 

 from 15 to 36 feet. 



Most of the buried soil so commonly reported in wells is probably the Sangamon soil devel- 

 oped at the top of the Illinoian drift, for well drillers usually report pebbles either in or imme- 

 diately underlying it. In all exposures along ravines in Decatur County in the vicinity of 

 Greensburg the black soil was found at the top of the Illinoian till, and in some the white clay 

 above it is still present. The till beneath the buried soil, wherever observed by the writer, is 

 oxidized to a depth of several feet. 



The record of a well near Letts Corners, obtained from the well digger, shows a black soil at 

 a greater depth than the exposures along streams would lead one to look for it. The lower part 

 of the section is also different from the customary bluff exposures. The well did not reach rock 

 at 83 feet, though rock is struck in neighboring wells at 20 to 30 feet. It appears, therefore, 

 to be in the line of an old valley. The lower beds may be alluvium, as suggested in the following 

 section : 



Section of Mitchell well, S miles west of Letts Corners. 



Feet. 



Clay, yellow, pebbly (Wisconsin till) 8 



Clay, blue, pebbly (Wisconsin till?) 45 



Clay, greenish (perhaps alluvium) 6-8 



Soil, black, with pebbles (Sangamon or perhaps alluvium) 3-4 



Clay, greenish, no pebbles noted (Illinoian or perhaps alluvium) 12 



Sand, thin. 



Clay, reddish 7-8 



85 

 BOWLDERS. 



Surface bowlders are common all along the border and, as already suggested, serve to 

 distinguish the Wisconsin from the outlying silt-covered drift, even where the former carries a 

 considerable admixture of silt. They are scarcely so numerous at the border as they are in 

 certain belts which traverse the inner border district (p. 84), but they are not less numerous 

 than over most of the region covered by the Wisconsin drift. Most of them are of granite and 

 are subangular rather than well rounded and do not show glaciated surfaces to such a marked 

 degree as do the rocks contained within the till. This scarcity of glaciated surfaces characterizes 

 the surface bowlders throughout much of the Wisconsin drift area in Indiana and in neigh- 

 boring States. 



In sees. 8, 9, 15, and 22, Nineveh Township, there are 40-acre lots upon which 1,000 or 

 more good-sized bowlders dot the surface; several in sees. 15 and 22 are 10 to 12 feet in 

 diameter. The disregard of surface elevation in their distribution is interesting. The belt in 

 sees. 8 and 9 is on ground 50 to 75 feet higher than in sees. 15 and 22, and in adjoining sections 

 bowlders abound both on the hills and in the valleys. This is mentioned as evidence that the 

 present surface is essentially the same as that left by the glacier, an interpretation that opposes 

 the view of D. S. McCaslin, 1 who held that in a number of localities heavy removal of clay was 

 revealed by the abundance of surface bowlders, and who cited sec. 16, Nineveh Township, as 

 a conspicuous example. McCaslin made a similar incorrect interpretation of a belt of bowlders 

 along a moraine in the northern part of the county. 



■ Thirteenth Ann. Kept. Indiana Dept. Geology and Nat. Hist., 1SS4, p. 124. 



