THE CARBONIFEROUS SYSTEM. 155 
THE BARREN COAL MEASURES. 
By the Pennsylvania geologists the term Barren Measures was given 
to the strata lying between the Mahoning sandstone and the Pittsburgh 
coal, in western Pennsylvania. These consist of alternations of sand- 
stone, shale, and limestone, to the thickness of about 400 to 500 feet. For 
the most part this series consists of shales which are peculiarly high- 
colored, being often bright yellow, red or blue, or red and yellow mottled. 
These constitute a peculiar feature in the geological column, and one 
which serves to identify the horizon at a-glance, as no such shales are 
found above or below. With these are interstratified numerous layers 
of nodular, frequently ferruginous, limestone. Here and there streaks 
of coal run through the strata, but they rarely become of workable thick- 
ness; and this is emphatically, as its name indicates, barren ground. At 
the summit of this series lies the Pittsburgh limestone, and above this 
the great Pittsburgh coal seam (Coal No. 8, or H), the first and lowest of 
the upper coals. 
Coming westward into Ohio, we find the Barren Coal Measures holding 
for a long distance almost precisely the character I have described. They 
are found to contain, however, in Columbiana county, even at the Penn- 
sylvania line, a workable seam of coal, our No. 7, above the place of the 
Mahoning sandstone. This may be the representative of the Elk Lick 
coal of Pennsylvania, or, as likely, a new element introduced into the 
series. In either case it is so continuous and important a coal seam, 
and is so closely associated with our group of lower coals, that I have 
classed it with them. Near Steubenville, however, we find the Barren 
Measures as completely barren as they are in Pennsylvania. Coal No.7 has 
there run out, and throughout the entire interval of 502 to 564 feet between 
Coal No. 6—the Steubenville shaft coal—and the Pittsburgh seam, which 
crowns the hills in the vicinity, no coal of workable thickness is found. 
Just at this point the Barren Measures are mostly shales, but on the oppo- 
site side of the river, and on the Virginia side of the Ohio for some miles 
above, they are replaced by heavy beds of sandstone.** 
* IT may here remark in passing that this region was peculiar for the formation of 
sandstones almost throughout the Coal Measures, as will be seen by reference to the 
sections given by Mr. Briggs in the annual report of the Geological Survey of Vir- 
ginia, under Prof. William B. Rogers. From these we learn that at New Cumberland, 
below Coal No. 7, sandstones fill nearly the entire space and cut all other coals to 
Coal No. 3, while on the opposite side of the river, a little above, this interval is 
filled for the most part with shales, and contains three workable seams of coal. A 
little further down the river, in Vineyard Hill, opposite Steubenville, which lies 
entirely above the place of Coal No. 7, that coal is cut out, and the Barren Measures 
are composed mostly of sandstone, as remarked above. 
