Part I. Report of progress in 1869, by J. S. Newberry, chief geologist. Part II. Report of progress in the second district, by E. B. Andrews, assist. geologist. Part III. Report on geology of Montgomery County, by Edward Orton, assist. geologist.

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The first of these includes those that do not coke and adhere in the
furnace, and are such as may be used in the raw state for the manufacture of iron.
The second group, to a greater or less degree, melt and agglutinate by
heat, forming what blacksmiths term a "hollow fire." This property
causes them to choke up the furnace and arrest the equal diffusion of
the blast through the charge. Hence they cannot be used in the raw
state for the manufacture of iron, but must be " coked." This process
of coking consists in burning off the bituminous or gaseous portion;
which leaves them in the condition of anthracite, except that, as this
change is effected without pressure, the resulting material is cellular and
spongy. Coals of this character, when free from sulphur-their great
contaminating impurity-are used for the manufacture of gas; the volatile portion, driven off in the retorts, serving the purpose of illumination, while that which remains is coke, and may be used as fuel.
The cannel coals have usually a more distinctly stratified structure,
are more compact and homogenous in texture, and contain a larger percentage of volatile matter than the others; also the gas they furnish has
higher illuminating power. Hence they would be used, to the exclusion
of all others, for the manufacture of gas, only that the coke which they
furnish is of inferior quality. They are therefore, for the most part,
employed as household fuels-for which they are specially adapted-and,
in small portions, for enriching the gas produced from coking varieties.
The marked differences exhibited by the kinds of coal I have enumerated, are doubtless due, principally, to the circumstances of their formation. The furnace coals have generally a distinctly laminated structure,
and are composed of bituminous layers separated by thin partitions of a
material allied to cannel, which does not coke. Hence the bitumen in
them is held in cells, and cannot flow together and give the mass a pasty,
coherent character.
The cementing coals have few such partitions, but show, upon fracture,
broad, brilliant surfaces of pitch-like bitumen. Both these varieties are
supposed to have been formed in marshes, where they were saturated,
but not constantly covered by water. The cannel coals were deposited
in lagoons of open water in the coal marshes, where the finely macerated
vegetable tissue accumulated as carbonaceous mud. Hence they have a
large percentage of hydrogen, and their gas has high illuminating power.
Hence also the remains of shells, fishes, amphibians and erustacea-all
aquatic animals-so generally found in them.
In Ohio, it chances that the lowest stratum in the series is generally a
furnace coal. Along its northern line of outcrop this is known as the
" Briar Hill coal." This coal enjoys a deserved celebrity for its adaptation to the manufacture of iron, and now furnishes the fuel by which half