132 Notice of Geological Surveys. 
tion of the stone was taken, and by the process of “ medal ruling,” 
a perfect engraving was made by the tracer, anda picture is given 
in the report (p. 230) of great distinctness. ‘The blue limestone 
abounds with the Strophomena of Raf., while the cliff has few 
of them. The sheil of the fossils is often preserved in the blue, 
while in the cliff limestone only the cast is found. 
6. The argillaceous shale, or “bituminous slate,” occurs 
next. This is black and highly fissile ; in some parts very bitu- 
minous and fetid, and when accidentally ignited will burn for 
several days. It absorbs water freely, and then exfoliates. It 
contains spheroidal septaria of an impure blue limestone, from a 
-few inches to three feet in diameter, that are filled with hee 
of carbonate of lime, or sulphate of barytes. 
It crops out ona line from the east side of Adams county, pass- 
ing north through Columbus, and is two hundred to three hun- 
dred feet thick. Balls of iron pyrites are found in it, which de- 
compose and-form copperas and alum. 
Mineral springs, charged with these and magnesian Pee abound 
in this and the bed of clay between it and the cliff limestone, and 
cause the numerous “licks,” which are now resorted to by do- 
mestic animals as they were formerly by the herds of wild ani- 
mals. 
7. The “ fine grained Waverly sandstone’ ; mene the shale. 
It is white, yellowish, purple and blue, but more commonly drab; 
more or less argillaceous in some parts, and contains oxide of iron, 
that causes ready decomposition—in others exceedingly compact 
and adapted to building, and for hearth-stones in furnaces. AS 
the superior rock, it. occupies, in the central part of the state, 4 
band running ahns east north east, twenty miles wide, and with 
a dip éast south east thirty feet in a mile, and a thickness of neal- 
ly four hundred or five hundred feet. The upper part abounds 
in Encrini, Ammonites, Producte, Terebratulz and Spirifere, and 
in the southern part of the state, Fucoides are found. A bed of 
clay appears to separate this from . 
8. A “conglomerate” or “ millstone grit, ” that underlies the 
coal measures, and which is generally composed of quartz peb- 
bles, and coarse-grained sand, or it assumes a fine texture and be- 
comes a hard compact sndetbns with but few pebbles, and crops 
out at short intervals in its line of junction with the sandstone 
in abrupt precipitous ledges of one hundred feet high. The ne 
