148 Bulletin of Laboratories of Denison University. Vol. xiii] 



many minor deltas laid down in ponded bodies which filled the 

 short but wide tributaries of the major valleys, so common in 

 these Mississippian-Pennsylvanian horizons, and have been sur- 

 prised at the little disintegration such slight deposits of sediments 

 have suffered. And the lapse of time since the Illinoian glaciation 

 is perhaps greater than is generally supposed. But concerning 

 the "smaller deltas" of the body of water in question : very dili- 

 gent search shows that there are no such deltas. 



Furthermore a detailed study of the boundaries of the Hanover 

 Dam shows the improbability of a ponded body of water having 

 been confined in the area, at least since long anterior to the earliest 

 glaciation. Gaps, A, B, and C, as shown on the topographic 

 map are low places in the rim of the basin that must have been in- 

 volved in such a static body. 



These gaps are tributary valleys of the drainage line now oc- 

 cupied by the Licking River. They have tended to keep con- 

 sonant grade with the major valley ; proof of this fact, however, 

 is observed only in valley A, the stream of which now flows just 

 east of the isolated rock hill at Black Hand station (Fig. 3) ; this 

 stream has hardly yet attained the grade of the major stream (Fig. 

 6), with which it possibly at a former time made its junction just 

 west of this isolated hill. This western outlet was maintained till 

 some progress was made in disintegrating the Black Hand forma- 

 tion; then a tributary of the stream that was at work in valley 1'., 

 because of variation in the structure of this formation, was led 

 headward into valley A, and captured its drainage. This episode 

 in the evolution of these gaps is mentioned for the purpose of 

 emphasizing their chronology. 



The slopes of the rock walls of valley C (Fig. 7), when plotted 

 downward, give a depth for the bed rock quite in harmony with 

 the record of the well-boring a short distance west of the line 

 along which this valley blends intt) the east-west filled xalley (Fig. 

 3). This well reaches a depth of about l.")(' feet below the general 



