426 GEOLOGY OF OHIO. 
other than the hard limestone burned by Mr. Dilz for quicklime a short 
distance further up the Auglaize. It thus appears that the black slate 
is not underlain in Defiance county by the Olentangy shale of Delaware 
county, but lies immediately on that which Dr. Newberry has designated 
the Corniferous limestone. This necessitates a hiatus in the Devonian 
series covering the Hamilton. If, however, the blue limestone be of 
Hamilton age, as claimed in the neighboring State of Michigan, the 
order of succession is unbroken. (See Geology of Delaware County.) 
There are indications of the outcrop of the black slate below the water 
of the Maumee at a number of places below Defiance, but at the dam at 
Independence are large slabs of black slate thrown up by the force of 
the water and ice. It continues in the river to within about eighty rods 
of the west line of section 24, where the hard limestone struck in the well 
at Gleason’s appears in the river and is quarried quite extensively. At 
Gleason’s and at Florida the black slate holds a bed of compact black 
limestone. It is used for all building purposes by the people, and has 
been burned into lime. It is thought by Mr. Gleason to be preferable in 
making hydraulic cement. It overlies a certain, unknown thickness of 
black slate, probably not less than ten feet. At Brunersburg Brice Hil- 
ton owns the land that contains the only outcrop of a lenticular, shaly 
limestone like that which pertains to the horizon of the base of the shale 
which by Dr. Newberry has been regarded as representing the Hamilton, 
but which, in reporting on Delaware county, the writer distinguished as 
Olentangy shale. It occurs in the Tiffin Creek. The stone is exceed- 
ingly argillaceous, and under the weather crumbles to a blueclay. This 
bed here is associated with the base of the black slate, and resembles 
other beds that occur in the Olentangy shale in Delaware county. There 
are large, loose pieces of the black slate in the river near this outcrop, 
but the exact relation to the shaly limestone is obscured by the Drift, 
and can not here be satisfactorily made out. It is said to occur up the 
Tiffin for a mile, but is not found below Brunersburg. Its position with 
respect to the southern boundary of the black slate indicates that it : 
overlies ten or twenty feet of the black slate. 
The Tully Limestone.—The hard, silicious, dark-blue limestone seen 
along both sides of the Auglaize in N. E. + section 9, Defiance, is the first 
below the black slate, and constitutes the uppermost portion of the Ham- 
ilton. It is believed to be the equivalent of the Tully limestone of New 
York. It is here extremely hard, crystalline, bluish-gray, and contains 
some crinoidal joints, calcite, and iron pyrites. It is somewhat vesicu- 
lar, especially the second course or layer, and embraces nodules of chert. 
It consists, so far as seen at this point, of the following section : 
