It is with regret and aversion that I return to the discussion of a subject on which I had hoped my last word had been written four years ago. Indeed, I would not do so if it were merely to continue the “Chester controversy” that began ten years ago, when Prof. Stuart Weller submitted a manuscript report on stratigraphic investigations in western and southern Illinois carried on by him under cooperative arrangements between the U. S. Geological Survey and the Illinois Geological Survey.
The author of the manuscript refused to accept my classification of the Chester series2 because he found it inapplicable to the Illinois section and erroneous in certain important respects. Following epistolary discussion of the disputed matters, we spent about a week of 1913 in a rapid review of the concerned areas in Illinois and Kentucky, accompanied by Mr. H. A. Buehler and Mr. Frank . . .