174 GEOLOGY OF OHIO. 
locations of the principal mines are shown, but no symbols are ventured 
upon to indicate the extent and reach of the field. The map is based 
upon one prepared a number of years since by Mr. James Nicholls, 
mining engineer, for Dr. Newberry, to accompany a volume in course of 
preparation. In the accounts that follow of the several mining cen- 
ters, the facts that are at hand bearing upon these questions will find 
place. 
Newberry has given a good account of the field in his report upon 
Summit county, vol. I, page 214, e¢ seq., and in his report upon Stark 
county, vol. III, pages 156-167, and also in his general discussions 
of the lowest coal. A knowledge of these previous statements will be 
presupposed in the descriptions that here find place. 
That this seam is really at the Sharon horizon (Newberry’s Coal 
No. 1), is established on the surest foundation. Every fact that ean 
have a bearing on the question is in harmony with this view. The 
sections above and below are in exact accordance. Below lies the 
Sharon conglomerate, which is, however, a very uncertain element, 
being frequently replaced by sandstones and shales, without a pebble. 
Under the Conglomerate is the Waverly group, consisting of the Cuya- 
hoga shales, the Berea shale, Berea grit and Bedford shale. All these 
are found in outcrop, and also in borings in due order, on every hand. 
The coal itself, in its mode of accumulation, and in its present 
disposition, agrees exactly with the Mahoning Valley coal. In physical 
properties the coal of the two fields differs somewhat, it is true, but no 
more than the most strictly continuous seams of the entire series will. 
differ when traced through an equal extent of territory. The Massillon 
coal is in a great number of instances covered by a few feet of black 
shale; this is, in fact, the normal cover, and this slate is charged with 
the fossils that are characteristic of the seam elsewhere. Above the slate 
come the Sharon shales with their nodules of iron ore. ‘These shales 
are very largely worked in Summit county for the manufacture of sewer 
pipe, and the character of the horizon is thus perfectly understood. 
The little “rider” seam of coal also comes into the sections frequently, 
30 to 50 feet above the main coal. It is nowhere large enough to be 
mined, but there is no reason to doubt that it represents the Quakertown 
coal of the Mahoning Valley, which is Newbery’s Coal No. 2. Still 
higher comes the Massillon sandstone, and above it, at the proper 
interval, the Mercer Group, the clearest and most unmistakable series 
of the Lower Coal Measures. 
