STRATIGRAPHICAL ORDER. 97 
Lower, or from 90 to 120 feet above the Middle Kittanning coal, No. 6, 
but it differs from the Lower Freeport in being of great economic value 
and interest, and in being universally known. 
Three of its elements unite to mark the horizon in the vicinity of 
Zanesville, viz., the limestone, the fire-clay and the coal. No black- 
band ore is known to occur with the coal in the Muskingum Valley. 
Contrary to the facts referred to on a previous page, the Upper Free- 
port coal is here mineable, well on to its western outcrop, and where it 
lies quite high in the hills. About Zanesville, it is commonly known 
as the Alexander coal, and it is quite largely worked in Washington, 
Perry, and other townships. It is always underlain by its limestone, 
and at Ballou’s Salt Works, 6 miles below Zanesville, the Upper Free- 
port or Bolivar clay has a good development, and is quite extensively 
worked. It has the same character as at Bolivar, Pennsylvania, and at 
many points along the line. It is a hard or non-plastic clay, with many 
green streaks of silicate of iron and alumina diffused through it. It 
does not attain the very highest quality as it is thus far shown in the 
workings. 
A combined section from Zanesville and vicinity is shown in Fig. 
X XI. The intervals used are all measured intervals in particular sec- 
tions. From the Putnam Hill limestone the section is continuous 
through Mill Creek valley and the Harper coal banks, up to Adam 
Rock’s mine, in the Alexander seam, except that the Lower Freeport 
seam was found 1 mile to the northward. 
One element only in this section needs to be described. It is No. 
15, and is designated as the Upper Putnam Hill limestone. The exact 
stratigraphical place of this stratum is not determined. There are but 
few occurrences of it known, and no one of these has been found in any 
section in which the Lower Kittanning coal appears. It is about the 
same distance below the Middle Kittanning coal that the Lower coal 
should be, and it may occupy the exact horizon of this seam. The best 
exposure of it ison Putnam Hill, directly above Putnam Station. It 
is there 27 feet below the Upper Zanesville coal (No. 6). It is a drab 
limestone, weathering yellowish white. It is fossiliferous, containing a 
Productus and other marine shells. Quite a heavy deposit of clay 
occurs in connection with it, and it bears an iron ore. These facts have 
suggested it as the equivalent of the Ferriferous limestone of Pennsyl- 
7 G. : 
