HOCKING VALLEY COAL FIELD. 991 
There are, of bone and coal together, 4 feet 4 inches in the 
section, but there is only one bench that is mineable, and this is 2 feet 
4 inches thick. Just why 8 feet should have been fixed upon as the 
popular measure of the seam, it is hard to see. Counting from the 
bottom of the bone to the top of the rider streak, there are 13 
feet in the section, and the coal could have been named the ‘‘ 13-foot 
seam” by quite as good a right. 
The horizon is well marked, even when the coal is wanting, the 
Maxville limestone (Sub-Carboniferous), or its clay, ore or flint 
being often found at nearly the same level. 
This horizon is found 80 to 120 feet below the Lower Mercer 
limestone. 
Asa key to the strata below the Mercer horizon, the following 
general section can be consulted. It will find its application only on 
the western margin of the Coal Measures of this region and considerable 
range in elevations must be allowed for : 
HONVET LCE CET ON DMG GIIIMESLONG a. ccscs ci ccaiscescscesesesencesece svctesicsece ee: 100 feet. 
Lower Mercer coal, O—15 feet below limestone. .........cecscceccsceeessees 95. “ 
Union Furnace block ore, extensively benched...................ssseeee SOM ay 
Dresden sandstone— Upper Conoquennessing— 
Very white and pure, 10-20 feet thick. Contains many im- 
pressions of trees, etc. Often replaced by thin stone 
and shale, in which case one or more coal blossoms 
occur. 
Mohler Coal—Quakertown coal or Coal No. 2.......cccccccessscescerseeseecs nO) 
Sometimes streaks of ore above and below. 
Massillon sandstone—often heavy. 
SharonyCoal=—CoalpNor lire ern cas ceteies «Sees sa sacs ss cee ae ous ove see bee tecdeaces 0} -¢ 
Sharon conglomerate—sometimes—pebbles coarse. 
Maxville limestone—often flinty, sometimes bears ore. 
Hard fire-clay—whole series 10 to 20 feet thick. 
Logan sandstone, often conglomeritic, pebbles small and usually 
flat. 
