422 



of the ice-sheet itself, rather than to the exact drift line. In interpreting 

 the Flatwoods phenomena the position of the advance of the ice-sheet itself 

 is of fundamental importance. This line of advancement, as given below, 

 was determined not only by the presence of erratic boulders and rocks, 

 but by stratified outwash material as well. Of the two phenomena, per- 

 haps the latter is the more important. 



A close examination of tbe hills or rather ridge extending eastward 

 along the northern part of section 15, T. 9 N., B 3 W., thence northeast 

 through section 11 and into section 1, shows that the ice-sheet never 

 crossed beyond. Evidence is plentiful in showing that the ice rested 

 against this ridge and remained close to it for some time. The west side 

 of the small adjunct is an outwash plain, which in the headwaters of 

 McBrides Creek shows the coarse layers of stratified gravel alternating with 

 both coarse and fine sand. About a mile west of the Stogsdill Pond is the 

 remnants of an old moraine, showing the last stand made by the ice front. 

 The coarse sand found in the ridge, dividing Flatwoods proper from the 

 adjunct, is partly outwash material and partly the result of the ice-front 

 itself in pushing material against the ridges, which the water later 

 worked over. Undoubtedly a tongue of the ice-front pushed up to the very 

 upper tributaries of the old stream, the lower part of which is now repre- 

 sented by McBrides Creek, but that it never crossed the ridge between the 

 old stream and Baccoon Creek to the east is certain. 



To the north the ice came up the White Biver slope and pushed up the 

 old stream, draining the region now occupied by Flatwoods proper. It 

 may have come up this old stream as far east as the Owen-Monroe County 

 line, and even some distance farther, but for the most time it must have 

 remained near the western border of the present Flatwoods. Alliston's 

 Branch has been eating its way into an old outwash plain since the with- 

 drawal of the ice from the region. It has erased the moraines, if any 

 were formed, and has taken considerable of the head of the outwash plain. 

 It is this outwash material, covered with later silt, that makes the slope 

 of the western part of Flatwoods toward the centre of the region. It is 

 evident from this that the ice-front for the most part did not extend 

 beyond the headwaters of Alliston's Branch, in sections 26 and 35, T. 10 

 N., B. 3 W. 



No outwash material or erratic boulders were found in the extension 

 of the Flatwoods basin into section 24, or on Chambers Hill, but erratic 

 boulders were found in the northern part of section 23 on the White Biver 



