THE CARBONIFEROUS SYSTEM. 151 
Coat No. 6a. (Norris 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 80 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. 
Coat 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. 
