SUPPLEMENTAL REPORT — HOCKING VALLEY. 905 



10. The ore next to be named is, beyond all question, the most valu- 

 able of the Ohio series. It lies at the very center of what has been our 

 largest and most successful iron manufacture therto. It is the chief 

 element in the geological scale of a large section, all limestones, coals, 

 and other ores being located as so much above or below this horizon. It 

 is known in the southern counties as the limestone ore, and the use made 

 of this designation suggests the importance of the seam. It is called the 

 limestone ore because it generally rests directly upon a well known lime- 

 stone, viz , the Gray or Hanging Rock Limestone; but there are two 

 other ores, at least, that have an equal right to this name — being asso- 

 ciated in the same way with limestones — yet both are ignored in common 

 use, and this name is applied to the seam now under consideration, 

 without uncertainty or ambiguity. The name, however, is in some ways 

 a misleading one; it suggests composition rather than situation, but 

 with the former it has nothing to do. Some lime enters into this seam 

 as into so many others, but the proportion is not nearly as large as in 

 other Ohio ores. Another design ition is commonly given to this seam 

 in Hocking and Perry counties. It is here known as the Baird ore. At 

 Union Furnace, Hocking county, it is styled the red ore. The identity of 

 these several ores has been fully established, and will be demonstrated 

 in a subsequent part of this report. 



Like the ores of the Coal Measures, the limestone ore is a carbonate or 

 siderite under heavy cover and a hydrated sesquioxide or limonite on its 

 outcrop. The varieties are known as gray or blue limestone ore and red 

 limestone ore, respectively. 



The gray variety is one of the best marked ores in Ohio, and is uniform 

 in character through all the district which we are considering. Samples 

 from Lawrence, Gallia, Scioto, Jackson, Vinton, Hocking, and Perry 

 counties cannot be distinguished from each other. Metallurgical suites 

 from the Hanging Rock Furnaces were collected during the progress of 

 the survey, and specimens of the gray ore came in the sets of the follow- 

 ing furnaces, viz. : 



Hecla - - Lawrence county. 



Monitor - " 



Vesuvius f - " 



^tna - " 



Lawrence - - 



Center , " 



Mt. Vernon " 



Buckhorn " 



Olive " 



Howard • Scioto county 



