36 BULLETIN OF THE LABORATORIES 



ing county it is flowing between almost vertical rock walls 200 yards 

 apart at flood plain. The valley again broadens toward Sugar Grove, 

 the main valley bearing northward while a somewhat lesser valley turns 

 southward both opening at once into the valley of the Hocking. 



A few miles above Sugar Grove Rush creek deserts both of these 

 outlets and has cut for itself a very narrow and picturesque gorge 

 among the hills along the south wall of the old valley. The whole 

 drainage of Rush creek seems to have been determined to run con. 

 trary to all the laws of hydraulics. 



The geological structure of the entire region is upper Waverly and 

 lower Carboniferous sandstones and shales dipping slightly to the south- 

 east. As far as observed the underlying rock structure has had no in- 

 fluence in the determination of the drainage lines. 



The glacial boundary through this region has been located by 

 Prof. G. F. Wright, at Lancaster. This will serve as a general bound- 

 dary but local extentions are to be expected. Extending all along the 

 valley east from Lancaster to a half mile beyond Junction City drift de- 

 posits, consisting of stratified and unstratified gravels and till are scat- 

 tered at high levels on both north and south walls of the valley. These 

 deposits extend for some distance south of Bremen down Rush creek 

 but none were observed beyond the county line where an old col un- 

 doubtedly existed. 



The most eastern till deposit occurs about Yz mile east of Junction 

 City where it fills the old valley 100 feet above the flood plain of the 

 creek and has caused a slight deflection of the stream to the south 

 around a large island like hill of Waverly. The rail road has here made 

 a deep cut through the till and revealed an excellent section. 



Besides the high level deposits which must be attributed directly to 

 the ice. All the large valleys are filled with river wash and silt. 

 At Lancaster this filling in the Hocking valley is at least 220 feet 

 deep. At a point about midway between Lancaster and Bremen rock 

 was reached by a gas well at 175 feet. At Bremen a gas well very 

 much to one side of the valley penetrated 65 feet of filling. 



Assuming a uniform grade in the old rock floor from New Lexmg- 

 ton to Lancaster the filling at Bremen would reach over 100 feet. At 

 the col on county line on Rush creek, the rock is only about 20 feet 

 below the level of the stream and about 50 feet above the valley floor at 

 Bremen. In Rush creek valley a few miles above Sugar Grove, the 

 rock is at least 118 feet below the surface near the middle of the valley. 



