THE CARBONIFEROUS SYSTEM. 151 



Coal No. 6a. (Norms Coal.) 



In the northern portions of the Ohio coal field we often find a trace of 

 coal, or a thin coal seam, about 50 feet above Coal No. 6, but this very 

 rarely becomes of workable thickness. In going southward it is first seen 

 in southern Tuscarawas and northern Guernsey county. It is there 

 local, but when present is thin and overlaid with a mottled brecciated 

 limestone, such as occurs higher up in the Barren Measures, but which 

 is quite unlike anything found below. 



South of the National Road, in Perry and Athens counties, a coal comes 

 in from 30 to 50 feet above the " Great vein," called by Prof. Andrews the 

 " Norris coal," which locally attains a thickness of six feet, but apparently 

 has not a very wide lateral extension. It is a coking coal, softer and 

 more sulphurous than that of the " Great vein," but in its best phases is 

 a good smith's coal, and one that will probably make a serviceable coke. 



Coal No. 7. 



Throughout Tuscarawas county, and in parts of Coshocton, Holmes, 

 Stark, and Carroll, we find a strongly marked coal and iron horizon about 

 100 feet above Coal No. 6. The coal is here of no great value — from eighteen' 

 inches to three feet in thickness — and is usually soft and sulphurous. 

 Resting upon it, however, is the most valuable deposit of iron ore in the 

 northern part of the State, and, indeed, one that is, locally, richer than 

 any other found in our Coal Measures. This is a blackband ore, which some- 

 times reaches a thickness of twelve feet, but is oftener three to six feet. 

 It is not a continuous deposit, however, within the territory it occupies, 

 and it runs out in every direction, so that it can be detected in but few 

 localities outside of Tuscarawas county. 



In some places, overlying this blackband ore — in others taking its 

 place — is a limestone which is usually nodular and so highly charged 

 with iron that it becomes a valuable calcareous ore. This is popularly 

 called Mountain ore, from the fact that it occurs in the summits of the 

 hills. It is also, locally, a limestone without ore, but containing some 

 iron, so that it weathers buff. 



The group of strata I have described is best shown in Tuscarawas 

 county, in the hills above Zoar Station, and those on the head of Stone 

 Creek and near Port Washington. In the first mentioned locality the coal 

 is three feet thick, but poor. The blackband and nodular calcareous ore 

 both appear above it, and have been extensively worked. At Wilhelmi's 

 ore bank, on Stone Creek, and at Port Washington, the coal is from one and 

 a half to two feet thick, is taken out with the ore and used in calcining it. 



