T. 0. Chamberlin — Diversity of the Glacial Period. 177 



Glacial Epoch], thus assuming the truth of his theory in the 

 title." I am puzzled to see how the title " The Terminal Mo- 

 raine of the Second Glacial Epoch " any more assumes the truth 

 of a theory than the title " The Unity of the Glacial Epoch." 

 If the purpose of the sentence was to convey the impression 

 that I commenced my consideration of the subject by assum- 

 ing the truth of the duality theory, it is precisely antipodal to 

 the fact. This paper was my seventh discussion of the 

 moraine or some part or phase of it. The first of these was 

 prepared while I entertained primitive and inherited views 

 closely similar to those which Professor Wright now advocates. 

 These views I gradually abandoned as my information increased 

 and my series of papers show a progressive change of opinion. 

 It was only at the close of my official work on the Wisconsin 

 Survey, when called upon to sum up and interpret finally the 

 results reached, that I definitely announced an abandonment of 

 the old view and an acceptance of the dual view, assigning 

 reasons therefor.* If anything relative to the history of my 

 personal views is of any importance in the matter (which is 

 not my assumption), it is this statement of change of view at 

 the close of several years of consecutive study, a statement 

 which had more of a final than of an inaugural character. 



The effort of Professor Wright to lay the groundwork of 

 presumption that my whole interpretation of the facts bearing 

 on the duality of the epoch is possibly a mistake by reason of 

 a change in my mapping in Illinois would have been without 

 force had he made a fair statement of the case. He states, 

 "in this preliminary monograph (see pp. 322-326) the moraine 

 is made to correspond with the kettle moraine of Wisconsin, 

 and to hug the southern shore of Lake Michigan, but in the 

 Seventh Annual Report of the U. S. G. Survey the later 

 glacial drift is carried down to Blooroington more than one 

 hundred miles farther south, while at the latest date Mr. 

 Leverett (Am. Geol., July, 1892, p. 23) specially deputed by 

 Professor Chamberlin to look after the moraines, draws his 

 later moraine line one hundred miles still farther south, through 

 Litchfield, Hillsboro," etc. (p. 353.) There is here a complete 

 omission of all reference to the provisional lines which were 

 marked with dots on the map in my earlier paper, and concern- 

 ing which the following was said in the text :f 



''There may be no more fitting place to make a qualifying 

 remark in regard to the whole region between the moraine 

 above traced and that adjacent to Lake Michigan. The drift 

 of this area bears undoubted evidence of being recent, and, 

 though this is in considerable part due, superficially, to aqueous 



* Wis. Geol. Sur., vol. i, pp. 271, 272. 



f Third Ann. Rep. U. S. Geol. Sur., 1883, p. 331. 



