ABANDONED PLEISTOCENE RIVER CHANNEL. 63 



the junction of the Little Flat Rock creek with the Flat Rock 

 creek, the old and the new channels approximately coincide. 

 The old channel has been modified and lowered to about the 

 level of that of the present streams. 



III. The old channel departs from the recent channel at the 

 point last described, and may be traced a little west of south to 

 Milford P.O. It is about thirty feet above the recent channel ot 

 the Flat Rock creek at the point of departure, and has but a 

 slight fall. The Flat Rock creek, in cutting its channel toward 

 the north from the point where it left this ancient river, has car- 

 ried away its water supply, leaving the abandoned part of the 

 old river a relatively high marshy region known to the early set- 

 tlers as " Beaver Pond." Recently an open ditch has been cut 

 through it converting it into fertile corn and wheat land. 



IV. From Milford the present Cliffy creek flows through 

 the old channel and has modified it, as in the case of the Little 

 Flat Rock creek above mentioned. 



If the Flat Rock and the Little Flat Rock creeks existed 

 contemporaneously with the old stream they, as well as Cliffy 

 creek, were tributaries to it at the points named as their conflu- 

 ence, and doubtless flowed at the same relative level and had a 

 less rapid fall than now. The evidence collected in regard to 

 the bed of the old stream shows that it ran over the Niagara 

 limestone in the upper part of its course with the exception of 

 the region between the Flat Rock creek and Cliffy creek (Sec- 

 tion III.), where it flowed over Pleistocene deposits of consider- 

 able depth as shown by well sections. One of these, just below 

 the C. C. C. & St. L. Ry. (see map), penetrated sand, clay, and 

 bowlder clay to a depth of 135 feet without reaching rock. 

 Another, a short distance below, is seventy-five feet deep in simi- 

 lar deposits without reaching their bottom. 



The facts so far observed do not show precisely when the 

 stream originated nor exactly how long it continued before its 

 waters were diverted into their present courses. Jt seems proba- 

 ble, however, that it originated immediately after the retreat of 

 the ice from the region, and was a part of the first definite system 



