28 GEOLOGY OF OHIO. 
By a comparison of the Lowellville section with this general sec- 
tion, it will be seen that the coal 30 feet above the Ferriferous limestone 
is the Lower Kittanning of Pennsylvania (Kittanning of Rogers, Coal C 
of Lesley). The well-known Kittanning clay-bed appears beneath it. 
Under the Ferriferous limestone a small development of the Scrub-grass 
(Upper Clarion) coal is seen. 
The Clarion (Lower) coal is wanting in the section, but the eight- 
inch coal, 50 feet below the limestone, will answer well for the Brook- 
ville coal (Coal No. 4, of Newberry, in Stark county). The distance to 
the limestone horizon is somewhat targer here than it is to the westward. 
The thin seams of coal above the Upper Mercer limestone obvi- 
ously represent the Tionesta coal. A seam ranging from 23’ to 4’ in 
thickness is found within a short distance on the other side of the river 
at this horizon. : 
The Mercer coals show for themselves, and need no comment. 
These are coals 3 and 3a of Newberry, in Stark county, and to the 
westward. 
The horizons of the Quakertown and Sharon coals are reached 
lower down, but neither of these inconstant elements appears in the sec- 
tion. The ore-bearing shales that overlie the Sharon coal are, however, 
distinctly shown throughout this region, and have been worked for the 
ore to a considerable extent. 
The distance between the Lower Mercer and the Ferriferous lime- 
stones in the Lowellville section is 148 feet, but this is in excess of the 
usual measure by 20 to 30 feet. The Lowellville measurement is in 
fact a maximum, while the same interval in adjacent sections, as shown 
by Newberry and White, is reduced to 105 or 110 feet. The average 
of 6 sections in the vicinity is 121’, and the usual measurements of this 
interval in Mahoning county will range between 105’ and 125’. The 
place of the Block coal is about the same distance below the Lower 
Mercer limestone that the Ferriferous limestone is above this stratum, 
so that the average distance of the Block coal in this region below the 
Ferriferous limestone is 250’. Its maximum would reach nearly 300 
feet. 
The outcrop of the Ferriferous limestone at Lowellville is the Jast 
one found in ascending the Mahoning Valley. None of the hills that 
border the valley above this point are high enough to reach its horizon, 
but the Mercer limestones continue in excellent and unmistakable de- 
