THE CARBONIFEROUS SYSTEM. 158 
the blackband, but is covered with a black shale which is highly ferru- 
ginous, and sometimes contains a few inches of good ore. On the Still- 
water and in northern Guernsey county Coal No. 7 is generally overlain, 
not immediately, but at a distance of a few feet, by a heavy bed of sand- 
stone, which is often a conglomerate coarser than that over No. 6, the 
pebbles sometimes attaining the size of a hickory nut. This conglomer- 
ate may be seen in Tuscarawas county, overlying the blackband and No. 7, 
in the hills between New Philadelphia and in the valley of the Connot- 
ton. It is here succeeded above by the brilliantly colored shales of the 
Barren Measures, which are never found below Coal No. 7. 
By Prof. Stevenson, who has traced all the lower coals through from 
the Tuscarawas valley to the National Road, the coal so largely mined at 
Cambridge, Guernsey county, is supposed to be our Coal No. 7. It is also 
the “ Alexander” coal of Muskingum county, which is thought by Prof. 
Andrews to be the “Sheridan,” or “ Bayley’s Run” coal, which reaches 
through, almost uninterruptedly, to the Ohio river. By many persons 
this seam is believed to be further extended into north-eastern Kentucky, 
and there to be the famous “ Coalton,” or ‘“ Ashland” coal, so much used 
in iron-making. This identification is, however, somewhat conjectural. 
In Muskingum county the Alexander coal (No. 7) is of varying thick- 
ness and value, but it is reported by Prof. Andrews to attain in some 
localities—Brush Creek and Wayne townships—a thickness of six feet. 
. At the mines of Mr. William Alexander, in Washington township, it is 
extensively worked, and has a good reputation. In this region it lies 
from eighty to ninety feet above the horizon of Coal No. 6, and is repre- 
sented by Prof. Andrews to have a limestone with iron ore a few feet 
below it. In Perry county this is the second seam above the “Great vein,” 
from which it is separated by an interval of from seventy to ninety feet, 
the “Norris coal” (6a) lying from forty to sixty feet below it. On Snow 
Fork the three seams may be seen in the same section at various places. 
Coal No. 7 is here from three to five feet in thickness, with limestone 
and iron ore generally visible below it. In Athens county Coal No. 7 is 
apparently represented by the Bayley’s Run coal. This is the seam 
most extensively worked, and regarded as the most important in the 
county, though hereafter it may be overshadowed by the working of the 
Nelsonville seam below drainage. The Bayley’s Run coal has been very 
fully described by Prof. Andrews in his reports on Athens county, and 
it is recognized as one of the most valuable coal seams of southern Ohio. 
Its thickness in Athens county is generally from four and a half to 
five feet. It is a coking coal, which usually contains considerably 
more sulphur than Coal No. 6, but in many localities it seems to be 
