55 



original drift surface. Samples 1-4 to 1-8 inclusive show per- 

 centages of clay and silt ranging from 91.% to °o.l3% and, 

 together with the laminated nature of the deposit, seems to in- 

 dicate a proglacial lake of early Kansan time. The extent of 

 Muh a body is not known at present. 



An examination of the analysis of the Kansan drift of the 

 overlying extramorainic till plain shows a mixture of greater 

 size range. The largest of the few grit and pebble fragments are 

 smaller than 15.85 mm. and the bulk of the material is medium 

 sand, fine sand, clay, and silt. 



The percentage of volatile matter was found to be approxi- 

 mately 10%. 



Following the pioneer work of Orton, McGee, and Winchell, 

 there were a number of studies of buried peat deposits in Iowa. 

 Various workers speak of pieces of cedar and tamarack wood, 

 several mosses, and occasional angiosperms being found in wells, 

 road cuts, and similar excavations. 



More recent work, such as that of Sears, Lane, Wilson, and 

 Yoss of this country and Erdtman of Sweden, has stimulated 

 further study of these deposits, especially of the pollen which 

 they contain. 



Small chips of wood were found throughout the sediment 

 described above. These are in a remarkably good state of pres- 

 ervation. They were embedded in celloidin, sectioned, stained 

 with Delafield's hematoxylin, destained with acid alcohol, and 

 mounted in balsam. An examination of some 40 slides showed a 

 predominance of spruce and tamarack. Several moss fragments 

 were found, none of which was in an identifiable condition. 



Pollen analysis was patterned after the method recently 

 suggested by Erdtman (1) except that the second treatment 

 with sodium chlorate and sulfuric acid was eliminated. Samples 

 of the residue obtained) were mounted in Erdtman's lacto- 

 phenol solution. No statistical analysis has been attempted to 

 date. 



Pollen from the following has been identified: Picea sp., 

 Abies balsamea, Pinus sp., Eetulaceae (perhaps Corylus), Acer 

 rubrum, Lycopodium complanatum, Lyco podium lucidulum, 

 Juglans or Carya, Juniper us or Larix, Primus? 



In addition to the pollen, several fragments of grasses and 

 sedges and a few trichomes were observed. 



