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Indiana University Studies 



farther inland than it could ever have been brought by the 

 ice alone. The morainic material has everywhere been car- 

 ried by the g-lacio-fluviatile streams beyond the actual position 

 of the ice-front. Occasionally debris has been carried in this 

 manner several miles beyond the position of the ice front. 

 Locally great outwash aprons occur, covering several square 

 miles. In the re-entrants between these expansions of out- 

 wash material there may be for a number of miles along the 

 ice margin comparatively little material of this sort. These 

 local expansions of outvv^ash material have frequently nearly 

 obliterated all the pre-glacial surface irregularities, and their 

 fairly even, eastwardly sloping surfaces may still be seen 

 descending from near the former position of the ice front. 

 These fans are now deeply trenched by post-glacial erosion. 

 Such an outwash fan occurs near the viaduct of the Illinois 

 Central railroad across Richland Creek, north of the mouth 

 of Beech Creek, and just outside the mapped area. Another 

 one is beautifully developed south and east of Park. It would 

 seem that broad sheets of water must have made this outwash 

 deposit of ice-contributed material, carrying it eastward two 

 or more miles. The sharp ravines and cuts next to the glacial 

 margin frequently expose layers of coarse gravel inter-bedded 

 with coarse sand. Farther east the gravel disappears, and 

 only the sand, very much cross-bedded and rudely stratified, 

 is seen in the sharp ravines and cuts. Much of the original 

 surface of this outwash fan is excellently preserved in sec- 

 tions 26, 27, 34, and 35. Its gently sloping surface shows 

 very clearly on the topographic map, tho deeply trenched by 

 post-glacial erosion. 



This outwash material in places almost completely obliter- 

 ated the prc-glacial topography. A small monadnock-like hill 

 one-half mile southeast is completely surrounded by stratified 

 sand. It would appear that this hill of Mansfield sandstone 

 stood island-like in the floods which swept the sands about 

 and beyond it. The pre-glacial valley of Cliffy Creek in the 

 eastern part of section 33, and thru the middle of section 34 

 was completely filled; and farther east in section 35 it was 

 filled from bluff to bluff to a depth of 100 feet. or more. It 

 is easily seen that Cliffy Creek never recovered this drain- 

 age, but sought an outlet to the southwest across the ridge 

 thru section 3. The line of the former discharge can be de- 



