THE PREGLACIAL DRAINAGE OF OHIO. 39 



Having now traced the several streams from which the 

 Little Miami was formed, and shown in what manner these 

 were united to make the present river, let us consider further 

 those parts of the preglacial streams which are not a part of 

 the Miami. Let us first return to the mouth of Turtle Creek and 

 examine that portion of Todds Fork which lies between the 

 point last named and Middletown. The old valley through 

 which this stream flowed is very conspicuous, and has long been 

 known. It was first mapped by Dr. Orton and published with 

 his article on Warren county in volume three of the Ohio Sur- 

 vey. 1 The width of the valley varies from about a quarter mile 

 to more than a mile, the latter width being found near Middle- 

 town. The valley is so flat that the old canal which extended 

 from Middletown to Lebanon was without locks. The depth 

 of drift in the valley is not known. Two wells have been found 

 in which the rock is reported to have been struck at a depth 

 of about twenty feet. This shallow depth may be due to an 

 old island now buried, or more probably to a slab of limestone 

 having been dropped in the old valley by the ice sheet and then 

 covered with drift. 



Two or three miles west of the mouth of Turtle Creek a 

 branch valley leaves the main one. This extends north and 

 east passing the city of Lebanon, where two deep wells only 

 a few hundred yards apart showed depths of drift of 126 and 

 256 feet. Just west of this city the wells which supply the place 

 with water showed only 90 feet of drift, but these were located 

 at the extreme side of the valley. Beyond Lebanon this old 

 valley can be followed to the Little Miami with which it unites 

 a mile or two above Oregonia. The bed of this -section of the 

 valley, however, is not flat. There is a rapid rise east from 

 Lebanon to a point about one mile from the Little Miami, where 

 the valley stands 190 feet above the adjacent river and 65 feet 

 below the table-land in which the valley is cut. From this place 

 the valley slopes rapidly to the Miami. The width of the valley 

 at the summit is between an eighth and a quarter mile. Only 

 twice in this tributary valley is rock shown in its bed ; once at 



1 Geol. Sur. of Ohio, Vol. Ill, p. 382. 



