405 
vraduially 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 7O00-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 38 and 10, ends 
abruptly in the rapidly headward-etching streams of the headwaters of 
McBrides Creek. The eastern rim is the ridge of highland which jas 
been mentioned as the western rim of the opening extending into the Rac- 
coon Creek 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 te the high ridge at the south, but 
subsequent drainage through sinks at the southern end 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 SOO 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 
