Ashburner.l 



344 



[March 18, 



vein " on the Roberts lot ; the limestone which is 6 feet thick and 40 feet 

 helow the " C " bed at Centerville, and the limestone bands and shales 10 

 feet thick exposed in a railroad cutting one mile east of the coal shutes of 

 the St. Mary's Coal Company, and 31 feet below the St. Mary's bed, are all 

 representations of the Ferriferous limestone. 



This conclusion is based upon a comparative study of all the individual 

 members of the rock sections in the three localities. On account of the 

 bad exposures in the Johnson run basin in the vicinity of the Roberts lot 

 and along Toby creek, and on account of the limestone in the two places 

 lying low in the valleys, it has always been difficult to determine the rock 

 thicknesses below the limestone. This fact has resulted in each case, of 

 placing the limestone too high in the measures, and consequently an error 

 in the identification. 



It is generally believed that no limestone occurs at St. Mary's. On 

 careful search an outcrop of the bed may be found on a hill north-west of 

 the railroad station. I have been told upon good authority that pieces of 

 stone have been gathered here which have been burned into lime. This 

 limestone is the same bed which is shown in Rogers' section (Vol. II, p. 

 522, Final Report First Survey). 



It has been reported that the limestone which was located by the assistants 

 of the First Survey was planted by persons having coal interests, with the 

 view of deception. Neither Prof. Rogers nor his assistants were deceived ; 

 the limestone which is placed in the section already noticed occupies exactly 

 the same relative position as that in the accompanying section. 



The Ferriferous limestone has a variable character throughout Western 

 Pennsylvania, so that a difference in the quality and thickness of the beds 

 in the three localities named do not argue against their identity. 



3. The character of the Dagus or Kittanning Lower bed, together with its 

 flooring and roofing strata, are found to vary considerably within the im- 

 mediate vicinity of St. Mary's, where its identity may be determined by 

 the engineer's level alone. 



The following analyses, made by Mr. A. S. McCreath, show marked varia- 

 tions in the chemical constitution of the coal : 



Color of ash reddish gray. 



Coke per cent , 60.655 



Fuel ratio 1:1.37 



lilac. 

 64.820 

 1:1.50 



pink. pink. 

 59.655 58 425 

 1:1.22 1:1.23 



a. Tannerdale mine, worked by St. Mary's Coal Company, two miles 



