922 GEOLOGY OF OHIO. 



K. CONNECTIONS BETWEEN THE SEVERAL PORTIONS OF THE FIELD. 



The foregoing statements as to the stratlgraphical order of the rocks of 

 the Hanging Rock District embraces the main result already reached. 

 The results have been stated as facts, and no proofs of the correctness of 

 the interpretations by which they have been reached have been given, 

 except incident dly. Inasmuch as a new place is here assigned to the 

 two most important horiz >ns of the district, viz , to Coal No. VI and to the 

 Gray or Hanging Rock Limestone, with the ore that covers it, the 

 grounds on which these changes are made will properly be demanded. 

 A brief statement of 'the facts which establish the ordsr here claimed,' 

 will, therefore, now be given. 



The Gray, or Hanging Rock Limestone, (Ferriferous of Andrews) 

 which constitutes, by far, the best known stratum of the district now 

 under review, was followed by Prof. Andrews as far north as Elk 

 and Madison townships, Vintjn county. The Nelsonville seam (Coal 

 No. VI ) was traced southward by him to the same townships. No exact 

 connection was established between these two important horizons, but 

 the conclusion was announced that the Nelsonville coal found its place 

 immediately bsloiv the Gray Limestone, constituting the Limestone Coal, 

 or No IVa, of our present series, and that " an entire change in the 

 deposits" began here and continued throughout the whole range of the 

 Nelsonville coal, (pages Gl, 72, 115,) Report of Progress, 1870) A mis- 

 take in the identification of the Blue or Zoar Limestone, with the 

 Putnam IliU Limestone, which prevailed in the work of the district for 

 the first two years of the survey, but which was corrected by Prof. 

 Andrews in Vol. I. of the Final Report, increased the confusion. 



The correctness o( Prof. Andrews's view was publicly called in question 

 by Andrew Roy, E-q , State Mine Inspector, in his Third Annual 

 Report, (repoit for 1876, page 153 ) Mr. Ri>y asserts the true place of the 

 Gray (Ferriferous) Limestone to be between Coals No. IV and No. V, and 

 frequently directly over Coal No. V, instead of over Coal No. VI. He also 

 declares this limestone to be the equivalent of the Putnam ilill Lime- 

 stone. 



On page 157 he also makes'the New Castle Coal, of Liwrenre county. 

 Coal No. V, and the Sheridan Coal, Coal No. VI, instead of No. VII, as it 

 had been previously counted. Either of these changes would go far 

 toward carrying the other with it. 



The result of the examination here recorded shows that Mr. Roy was 

 entirely right as to the last point and substantially right as to the first. 



For the purpose of determining the true order through thi^ unsettled 

 portion of the field, a line was selected which connected the Nelsonville 



