403 



gradually from the bank of the pond for about one and one-fourth miles 

 to the south, and in its lowest place, a series of sinks jutting against 

 the bed-rock hills at the south, comes down to the 700-foot contour line. 

 This adjunct basin is about as broad as long. It is drained mainly by 

 two southward extending streams that come to the series of sinks at the 

 south end. A third but much smaller southward flowing stream drains 

 the western side- It also disappears in a sink in the southwest corner of 

 the region. The western edge, near the middle of sections 3 and 10, ends 

 abruptly in the rapidly headward-etehing streams of the headwaters of 

 McBrides Creek. The en stern rim is the ridge of highland which has 

 been mentioned as the western rim of the opening extending into the Rac- 

 coon Greek Valley. This same ridge turns to the west and forms the 

 southern rim of the adjunct basin also, and beneath which the waters of 

 the region flow in their underground passage. This small adjunct basin 

 undoubtedly once had a smooth and gentle slope from the southern rim of 

 the western part of Flatwoods proper to the high ridge at the south, but 

 subsequent drainage through sinks at the southern eud has eroded it into 

 three main grooves with many smaller tributary grooves. The slope be- 

 gan at the north at an elevation of more than 800 feet, and ended at the 

 southeastern corner at 740 feet. The west part of the southern end was 

 somewhat higher, perhaps 760 feet. It was lowest at the southeast corner, 

 because at this place there is an opening in the bed-rock ridge, which 

 leads to Raccoon Creek. This opening will be called into account later. 



We are now ready to go back to the broad opening in the middle of 

 the southern periphery of the basin, and see the extension of the Flatwoods 

 basin to the south. As has been said before, the floor of this opening is 

 slightly below 740 feet, and that the silt line extends as high as 760 feet. 

 Soon after leaving the opening, the silt line on the side of the ridges be- 

 comes more or less indistinct, since erosion has either erased it or covered 

 it over. Still farther south not only the silt line is removed, but much 

 of the one-time basin-flat itself is removed. The flat, however, can be 

 traced for four and one-half miles south and some west down the valley, 

 or rather above the valley of Raccoon Creek. The creek here turns 

 abruptly and flows to the northwest, at a right angle to the course above. 

 Modified portions of the old flat are distinct for two or more miles north- 

 west of the sharp turn. 



It is understood, then, that this Raccoon Creek addition is very much 

 eroded by the present stream and its tributaries. But it is important to 



