Geological Survey of the State of Ohio. 357 
have been deposited first, while the finer particles would be borne 
far out into the ocean. In some instances, the pebbles are de- 
posited in layers, as though in a turbid state of the water, nothing 
but pebbles were deposited, while, in a more tranquil i no- 
thing but comminuted sand. 
V. Lower Coal Series.—These consist of alternations of sand- 
stones, shales, limestones, iron ores, and coals, to the thickness of 
300 feet. In this belt, which extends through the State in an 
E. N. E. direction, are embraced the most valuable deposits. 'The 
sandstones are quarried for building, gravestones, and grindstones. 
The limestones are used as fluxes at the furnaces. Many of them 
are burned for quick-lime. One stratum, from the fineness of its 
texture and compactness, takes a very high polish. It can be 
used to advantage asa marble. Many of the shales, on disinte- 
gration form good fire-clay. But the most valuable members of 
this group are the coal and iron ores. There are two distinct beds 
of coal. The lower one is of a superior quality, and at no re- 
mote day, will be extensively mined for fuel. In reference to the 
extent of this deposit in Jackson and Lawrence, Mr. Briggs says: 
“ The whole amount of coal between these points, from the Ohio river, 
north, to the Hocking valley, may be safely estimated as sufficient to form 
an entire stratum of fifty miles in length, five miles in width, and nine 
feet in thickness, ‘This amount of coal will yield about 9,000,000 of tons 
per square mile. This estimate includes but a very small part of the 
coal, which can be obtained from the beds heretofore described ; for, after 
disappearing beneath the water courses, they doubtless continue east- 
ward, toward the Ohio river, sinking deeper and deeper beneath the sur- 
face, so that they can be reached only by shafts near the Ohio, at the 
depth of some hundred feet.” p. 87, 
Equal in importance are the iron ore deposits. They are rich, 
—some of them yielding 60 per cent.,—and easily wrought. From 
their juxtaposition with the coal and limestone, it requires little 
foresight to predict that this branch of manufacture will become 
a great and inexhaustible source of revenue to the State. On 
page 93 we have an estimate of their extent. 
“At avery low calculation of the amount of good iron ore in the re- 
gion which has this season been explored, it is equal to a solid, unbroken 
stratum, sixty miles in length, six miles in width, and three feet in thick- 
ness. A square mile of this layer—being equivalent, in round numbers, 
to 3,000,000 cubic yards—when smelted, will yield as many tons of pig 
