20 
Earl R. Scheffel 
part of the first or outer moraine of the Miami Lobe of the Late 
Wisconsin ice where it forms the east bluff of the Great Miami 
River south of Dayton.^ 
General Discussion of Eskers. Much question and dispute has 
arisen in the past concerning the terminology^ for certain ridge- 
like products of glaciation, but the designation '^esker’’ is gen- 
erally applied by American geologists to lines of debris presum- 
ably aggraded by streams between walls of ice. Though the 
theory of deposition in sub-glacial tunnels® holds the greatest 
credence today, the en-glacial and super-glacial or various com- 
binations of the three theories have been oflFered as plausible 
explanations in specific instance. ^ For convenience this article 
assumes in the beginning that the Dayton ridges are eskers, and 
that they were formed in sub-glacial tunnels. 
Preliminary Description of Region (fig. i). The northern end is 
known locally as ‘‘The Bluffs.’’ These trend east-northeast to 
west-southwest about half a mile, presenting an abrupt slope 
considerably over one hundred feet high toward the valley of 
Dayton to the north. The Miami canal runs along the slope not 
far from its bottom, and below this at the base of the Bluffs flows 
the Great Miami River. The topography of this and also of the 
western half of the area presents a beautiful study in kames; 
mounds and basins® are abundant. The mounds or knolls fre- 
quently show a tendency toward alignment, producing ridges. 
The eskers indicated on the map constitute the eastern boundary 
indebted to both of these gentlemen for their courtesy. He also wishes to thank 
his instructor Professor Carney, for going over the field with him and taking the 
several excellent photographs illustrating this article. 
^ F. Leverett, Monograph XLI, U. S. Geol. Surv. (1902), p. 355. T. C. Cham- 
berlin, Annual Report, U. S. Geol. Surv. (1881-1882), p. 334. 
® G. F. Wright, The Ice Age in North America (1891), p. 296; G. H. Stone, 
Monograph XXXIV, U. S. Geol. Surv. (1899), pp. 35, 359. W. C. Morse, The 
Ohio Naturalist, vol. vii, (1907), pp. 63-65. 
® Chamberlin and Salisbury, Geology, (1906), vol. iii, pp. MItTIT 
^ W. M. Davis, Proc. Bos. Soc. Nat. Hist., vol. xxv (1892), pp. 477-499; J. B. 
Woodworth, Proc. Bos. Soc. Nat. Hist., vol. xxvi (1894), pp. 197-220; O. H. 
Hershey, yfm. G^’o/., vol. xix (1897), pp. 197-209, 237-253; W. O. Crosby, Am. 
Geol., vol. xxx (1902), pp. 1-39. 
^ T. C. Chamberlin, loc. cit., p. 334. 
