STRATIGRAPHICAL ORDER. 95 
Ames limestones also continue through the field to re-enforce and con- 
firm the sections built from the elements of the lower coals. 
No sections from the Coal Measures of Ohio are better known than 
those from Zanesville and vicinity. Foster of the first Survey, New- 
berry and Andrews of the second, have all made frequent use of them, 
and frequent appeal to them. Andrews gave a name to one of the most 
widely distributed limestones of the Lower Coal Measures of Ohio from 
Putnam Hill, opposite Zanesville. The Kittanning coals are familiarly 
known through several counties as the Lower and Upper Zanesville 
coals, both of which are largely worked within the corporation limits. 
The leading elements are as follows: The Lower Mercer limestone 
and coal are found, as has been already said, in the bed of the Mus- 
kingum at low water, and almost everywhere to the north and west 
where their horizons are exposed. The Upper Mercer limestone and 
coal are found, one or both, in most of the sections, but the limestone 
is, as usual, less reliable than the companion seam below. It is very 
often replaced by fiint. The usual interval is 25 to 30 feet. 
The Tionesta coal is shown in probably two out of three sections 
that cut its horizon, at 5 to 15 feet above the Upper Mercer limestone. 
The Clarion? (Lower) coal is represented in many sections by a 
seam, seldom exceeding 16 inches in thickness, that occurs 15 or 20 feet 
above the Putnam Hill limestone. It is the No. 4a of several localities. 
A heavy sandrock comes in between the Lower Kittanning coal 
and the Putnam Hill limestone in the vicinity of Zanesville. It is 
quarried quite largely, and furnishes a building stone of unusual excel- 
lence. Where it occurs, the interval between the two elements last 
named reaches or exceeds 60 feet. The Lower Kittanning coal is 
known as the 4-feet seam throughout this district, and the Middle 
Kittanning coal as the 3-feet seam, these names agreeing with the com- 
mon measurements in mines of the several seams. The interval be- 
tween these coals ranges from 16 to 32 feet. The most common meas- 
urement is 28 feet or thereabouts. 
The Lower Freeport coal is not unknown, but it is generally too 
thin to repay working. Its place is 50 to 70 feet above the Middle 
Kittanning. It carries with it a valuable bed of clay throughout por- 
tions of Muskingum and Perry counties, which is known from the 
locality of its best development as the Moxahala clay. 
The Upper Freeport horizon is found about 50 feet above the 
