152 The Ohio Naturalist. [Vol. IV, Ko. 7, 



glacial history of the region. Near the western end, Pleasant 

 Run enters the abandoned portion of the valley- from the north, 

 flows diagonally across it toward the southwest and enters a nar- 

 row valley about one mile long, the southern end of which opens 

 into the Hocking valley. This narrow valley is about 300 yards 

 wide at its narrowest point and is bordered by ver}^ steep rock 

 walls 150 to 200 feet high. The floor is a level plain, in every way 

 a continuation of the floor of the larger valley. There are no well 

 borings which might show the depth of drift. It is not in a 

 position for an oxbow of either the Hocking or the stream which 

 formerly occupied the abandoned valle}'. It is possible that there 

 may have been a low col in this narrow \-alley over which the 

 waters from the east poured after their outlet at lyancasier had 

 been blocked by ice but before the present outlet had been cut. 

 Subsequent advance of ice might have blocked this outlet and the 

 present drainage have been developed. 



Little Rush Creek rises in Perrj^ county near New Reading and 

 flows westward into Fairfield county, entering Big Rush Creek 

 at Bremen. In its upper course its valley is broad and two and 

 one-half miles northeast of Rushville a depth of 160 feet was 

 reached with no rock. A short distance above Rushville it begins 

 to narrow. At the station a depth of 40 feet was penetrated with- 

 out encountering rock, but a few hundred yards below, the valley 

 becomes extremely gorge-like and the stream flows on rock, 

 everything indicating the site of a col. This region was probably 

 drained to the northwest into the preglacial outlet of the Mus- 

 kingum, although the channel is now diftlcult to trace. A low, 

 broad depression extends from a short distance above Rushville 

 through to this old valley. 



Clear Creek enters Hocking from the west about three miles 

 below Sugar Grove. Its headwaters are in a rolling, drift-covered 

 region not far from the headwaters of the Hocking, but its valley 

 first becomes well defined near Amanda, where it is more thnn a 

 mile wide and is bordered by rock hills. It narrows graduall>-, 

 how^ever, and near Revenge becomes very gorge-like although 

 there is a flood-plain several hundred feet wide. About four 

 miles above its juncture with Hocking, it narrows perceptibly 

 until the flood-])lain is not more than 100 yards in width, the hills 

 being very abru])t and about 200 feet or more in height. Below 

 this point the valley widens somewhat but not much. This nar- 

 row^ point is an old col. The preglacial outlet of Clear Creek is 

 buried beneath drift deposits but was probably northwest from 

 Amanda into the vScioto. 



A valley extends from Lancaster southwest to Amanda, con- 

 necting the Clear Creek and Hocking valleys. At Lancaster it 

 is about one mile wide but it narrows until, at Delmont five miles 

 distant and 250 feet above Lancaster, it is about 300 yards in 



