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 blue clay. 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. J 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 : 



