134 



IOWA ACADEMY OF SCIENCE 



Loess 



Kansan 



Drift 



Aftomax 

 Soil 



Sue- 

 Aftomax 



TlLL 



Feet 

 7. Loess, 1 ft. of soil at top, grading below 

 into brownish yellow to buff loess, wholly 

 leached of calcareous material, mantles the 

 eroded surface of the Kansan drift; thick- 

 ness at the summit 8-10 



6. Ferretto zone at the top of the till, absent 

 from the slopes, reddish brown, leached, 

 pebbles show considerable decomposition; 

 thickness 0-1^ 



Grades downward into: 



5. Till, brownish yellow to yellow, summit 

 rounded, leached of calcareous matrix and 

 limestone pebbles in uppermost 7 to 8 ft., 

 calcareous below with lime concretions 

 and limestone pebbles, insoluble drift peb- 

 bles present throughout, lime concretions 

 most abundant just below the base of the 

 leached portion; maximum thickness 25 



Grades downward into: 



4. Till, blue-gray or slate-colored, containing 

 two large sand pockets, a and b, which 

 have the appearance of included bodies, 

 sand pocket a lies in the transition zone 

 of (4) and (5), matrix of till calcareous 

 and limestone and other drift pebbles pres- 

 ent, fragments of wood in the basal portion, 

 fills an old depression; thickness 0-28 



3. Old black soil, with many small fragments of 

 wood mineralized with iron pyrite, pebbles 

 rare, some imperfectly laminated clay, soil- 

 zone delineates an old depression with 

 slopes as high as 12°. At c, on an old 

 track level (Fig. 13, B), is a stump with 

 roots and rootlets running through the 

 old soil and underlying clay; the wood is 

 mineralized like the fragments of wood 

 throughout the soil zone. Thickness of 

 soil zone 2^-3 



Grades downward into: 



2. Till, dark bluish green on damp surface, 

 light grayish green where dry, leached 

 of calcareous matrix and limestone pebbles 

 but other drift pebbles are present; thick- 

 ness 6± 



Grades downward into: 



1. Till, yellowish to brownish green, with some 

 maroon-colored material in the lower part, 

 leached 2-4 ft., calcareous below; thickness 

 exposed 0-14 



