CLAY DEPOSITS. 661 
The Coal Measures extend 1000 feet higher than the section in- 
dicates, including the Barren and Upper Measures, but no notable coal 
occurs and no clay bed worthy of mention. The clays of the Barren 
Measures are mainly red and irony; they have been turned in small 
quantities to various uses, but have no prominence in any. The clays 
of the Upper Coal Measures are regularly found under the coals, but 
are put to no use as yet. They are mostly present in small amounts, and 
are, like the coals, rarely of any economic value, the Pittsburgh seam 
being the only one that holds high rank in Ohio. 
The lowest clay in the Coal Measures, the Maxville or Sub-carbonif- 
erous limestone clay, has its most prominent development in Ohio in 
and about Sciotoville, Scioto county. This name for the clay is not a 
recognized one, but its most characteristic associate rock is this lime- 
stone, which, in the famous Kentucky clay mines, lies in heavy cliffs 
just over the massive clay. It is frequently called the Sciotoville clay, 
as that place is the center of its development and use. The clay underlies 
the limestone directly or is separated by a thin streak of coal, which is 
supposed to be on the horizon of coal No. I, or the Sharon coal, but so 
far no section has been obtained in which the true and unmistakeable 
Sharon coal and Maxville clay both figure. The deposit is first found 
in the tops of intersecting ridges near Portsmouth, occasionally overlain 
by nodules of limestone, but no coal ; at Sciotoville, eight miles eastward, 
the hills are all high enough to hold it and its best development is here ; 
at Webster, thirteen miles further on, it is at drainage level, and shortly 
after dips under the surface. On the Kentucky shore and for forty miles 
to the south-east, it has a very heavy development. The clay runs from. 
1 ft. to 5 ft. thick, averaging 2 ft. 6 in. It is benched where practi- . 
cable, drifted where necessary, and it is all. mined by powder. It is 
grayish-drab in color, full of blue organic stains, but of remarkable purity 
and excellence. It is very hard and flinty, but runs soft in places, so 
that plastic clay need not as a rule be imported. 
Another small development of this clay is found near Logan, Hock- 
ing county, where it supports the manufacture of a good fire brick. Its 
main development is to the north-east of Logan, but in various places to 
the south-east it is also mined. It disappears under drainage three miles 
north of Haydenville. It is about three feet thick, and quite pronounced 
in character as a flint clay. The western townships of Vinton county 
also hold this clay in fair development, but at present so far from rail- 
