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slope, away from the high periphery at this part of Flatwoods. It is 

 improbable that this immediate portion was ever covered with ice, or if it 

 was, only for a short time. 



The headwaters of Big Creek in sections 24, T. 10 N., R. 3 W., and 19, 

 T. 10 N., are in outwash material, and erratic boulders are common. But 

 these conditions are not found on the Flatwoods side of the divide. It is 

 very probable that the ice-front never got over this divide, although the 

 waters came freely into the Flatwoods region over this divide in the 

 southwest corner of section 19. 



But little attention was given to the probable front of the ice east of 

 Big Creek, but indications are that it pushed up Jacks Defeat valley to 

 near the middle of section 28, T. 10 N., R. 2 W. Its maximum advance 

 east of Jacks Defeat was probably where indicated by Leverett. Yet it 

 seems to the writer, for reasons that will appear later, that for the greater 

 time it must not have been farther south than the middle of sections 21 

 and 22, T. 10 N., R. 2 W. 



The line of the advance of the ice-sheet south of Freeman was proba- 

 bly as indicated by Leverett. The advance was somewhat east of Free- 

 man and continued northeast to near the southwest corner of section 23, 

 T. 9 N., R. 3 W., where it turned northwest, jutting against the high ridge 

 extending northward and northwest to the southeast corner of section 9. 

 Here the ice crossed the ridge and protruded eastward, as already de- 

 scribed. But it is not likely the ice-front was east of Freeman during the 

 time of the formation of the basin flat. The material of the flat west of 

 Freeman is principally sand, and quite likely is the lower end of an out- 

 wash plain. 



Although the above details show the tracing of a line for the advance 

 of the ice-front, it must be continually borne in mind that the ice-front 

 was not irregular in outline, but that it was constantly changing in a sort 

 of backward and forward movement, due to the seasonal changes in tem- 

 perature. This line, as described above, has practcially all of the Flat- 

 woods region outside of the ice limit, and in some places several miles 

 within the limit placed by Leverett. Some glacial material was found 

 well outside the limit as traced above, but it was material carried there by 

 currents of water, and is not to be interpreted as being direct evidence of 

 the presence of ice. Again, it is possible that the extreme limit of the ice- 

 sheet came as far as indicated by Leverett. But it is quite evident that it 



