54 



face; 1-4 from the rock flour immediately above the peat; 1-5, 

 1-6, 1-7, and 1-8 spaced at intervals of 5 inches through the 

 seam; and 1-9 from the Nebraskan drift. 



MArmkon Drift 



Section showing location of interglacial peat deposit. 



The Kansan drift, 1-1 to 1-3 inclusive, appeared much like 

 the rock flour below except that there were a number of grit 

 fragments and pebbles present in the former. Directly above the 

 peat was a bed (1-4) of very fine rock flour showing what was 

 interpreted in the field as varves. The peat seam, 1-5 to 1-8 

 inclusive, a deposit 20 inches in thickness, appeared to be richest 

 in organic matter near the middle. Pieces of this peat are readily 

 broken along the contact line of the thin laminations. Sample 

 1-9, the Xebraskan drift, is a well-weathered, sticky, dark gray- 

 black earth, with a few pebbles showing considerable disintegra- 

 tion. 



A laboratory study of the deposit was made to determine the 

 physical nature of the environment and the organic matter 

 present. 



To retrieve any plant fragments in the samples it was neces- 

 sary to loosen the particles of soil from one another. This was 

 accomplished by adding distilled water in excess, then gently 

 stirring and mashing the resulting mixture with the fingers. 

 After the wood fragments were removed, the mixture was 

 evaporated to dryness in an oven. The dried lumps were crushed 

 between the fingers and later screened, using the Tyler Standard 

 Screens for the analysis. 



High percentage of clay and silt is characteristic throughout 

 the series but especially through the peat and the member 

 directly above. Sample 1-9 shows a silt and clay content of 

 79.61% which is in accord with analysis made by Kay and 

 Apfel (2) for Nebraskan drift. It is also noteworthy that there 

 are no rock fragments greater than 1.96 mm. which may par- 

 tially be accounted for by the very thorough weathering of the 



