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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By reference to the map of grouped sections, it will be possible to see
at a glance the lower division of the productive coal measures of this
part of Ohio, extending from the top of the Logan sandstone group to
the Putnam Hill limestone.
For the most part, the strata tell a story of comparatively quiet waters.
At first we have a limestone-making period, during which, in limited secluded basins, limestone gradually accumulated, while at the same time
in other places the stronger currents carried sandy materials, which are
now found reposing at the same level of the limestone. Succeeding these
we have similar scenes of quiet and also of moving waters, the former
depositing fine shales and clay sediments, and the latter sandstones and
sandy shales.
At a few points there were small basins in which thin layers of limestone were accumulated. There were also insular places on which the
vegetation of the coal grew, which produced thin seams of coal. There
was, doubtless, much vegetable matter carried into the waters, from
which was evolved carbonic acid, which uniting with the iron oxides
diffused in the waters and sediments, caused the formation of the common proto-carbonate or Siderite ore of iron. Some of the ores constitute
regular layers, implying a regular deposition like other sedimentary
strata; but for the most part the ores are in nodular form, often in large
flattened discs, in which the well known laws of segregation came into
play.
The iron ores, so far as they have been examined, are of the Siderite
(proto-carbonate of iron) class, the exterior surfaces, which have been
exposed to atmospheric agencies, only being changed to the sesqui-oxide
of iron.
The carbonic acid might, in some cases, have originated in marine
vegetation, which, in the form of Fucoids of the type of Spirophyton
cauda-galli, was very abundant at certain periods during the formation
of the strata of this lower coal-measure group.
There was a tendency to the formation of flint in connection with the
layers of iron ore found about 30 feet below the Putnam Hill limestone.
This stratum is far below the flint or buhr of Flint Ridge. The flint of
this lower stratum was used by the aboriginal inhabitants for their
weapons, and pits whence the flint was dug are not uncommon.
There is a thin seam of cannel coal a few miles south of Wolfe Station,
in Perry county, on the Zanesville and Cincinnati Railroad, which was
formerly mined for distillation into oil. No measurements were made,
the old workings having fallen in. It belongs to the lowest part of the
coal measures, but its exact stratigraghical position is not known, but
will be ascertained hereafter.
Having thus given sections of the rocks of the lowest division of the
productive coal-measures in the north-western portion of my District,