238 The Ohio Naturalist. [Vol. VIII, No. 3, 



Reticulation. The two eskers show several connecting 

 branches. This inipHes a union between the Hnes of drainage 

 some time during their existence. These connecting branches 

 are so depressed in parts that tracing is difficult. Such a condi- 

 tion would be natural as the cross drainage would normally be 

 so sluggish that the tunnel carrying it would probably never 

 attain a large size. It is a question whether the two eskers r>: pre- 

 sent branches from one line of drainage or are entirely indepen- 

 dent. They may even represent a shifting of drainage lines. 

 The lower end of No. 1 suggests by its position (Fig. 1) that it 

 may be a branch from No. 2, rather than a continuation from the 

 head end of No. 1, as we have described it. 



Fig. 4 (Z*^. Cai'iiey). Camera reversed from fig. 3, and view taken 

 looking south on same esker. 



'r5 



Knolls. Hummocks are frequent. Generally they mark the 

 southern termini and ridge junctions. At its head end No. 2 is 

 composed of a series of four joined together. Many theories^" 

 are given for the origin of such swellings. In connection with 

 knolls other modifications of the esker type may be noted. 

 Several buttress-like deposits were found lying against the bases 

 of the eskers; sometimes also a fan-like spreading of debris froin 

 a similar position was observed. These irregularities probably 

 mark the entrance to the major line of small tributary streams, 

 or as an alternative, the opposite condition, leakage from the 

 major lines. The knolls at the head of No. 2 arc more sugges- 

 tive of tributaries than of kames. 



The knoll-endings (Figs. 1, 6) on the Miami Valley suggest by 

 their alignment that they have been cut off at this point by the 

 Miami River. Though this stream here turns to the westward, 

 the even floor of the vallev is evidence that it formed v turned 



20. J. B. Woodworth, loc. cit.. pp. 202, 203. 



