76 



Professor Orton, in the (ieological Keport of Ohio, Vol. Ill, page 'ASo, men- 

 tions a mass of Clinton Limestone sixteen feet thick and covering three-quarters 

 of an acre, quite behjw its geological horizon and resting on glacial clays and 

 gravels which separate it from the blue limestone of the Cincinnati rock beneath. 



The subject of this paper is a mass of upper silurian rock, Niagara limestone, 

 or more likely, Niagara and Clinton. It is clearly a drift deposit and was originally 

 the greater part of an acre in extent. It is difficult to say just what is its area as 

 it extends back from the hill-slope, where it is exposed, under a heavy deposit of 

 later, modified drift. The Evansville & Kichmond Railroad, which was never 

 finished further than the road bed, cut through it a few years since to its full 

 depth, or very nearly. Portions of the border of this rock moraine had been ex- 

 posed for time unknown by erosion. A mixture of clay, sand and a variety of 

 small boulders separates this deposit from the Hudson Eiver rock of the Lower 

 Silurian. 



Fig. 1 gives a view for near 70 yards east and west. It has been five years 

 since the rocks were cut through, and as a consequence the superposed loose ma- 

 terial has drifted over the ledges and into the crevices, partially obscuring the 

 promiscuous jumble of the separate masses. Still it can be seen that the coarse 

 chunks of various sizes and forms are jammed together at all angles. 



Fig. 2 represents an instance of a large block glaciated on the under side. 

 The use of a glass will aid in discerning the well-marked stria\ One or more 

 observers who have examined the deposit are of the opinion that the rock was 

 glaciated from above while in place, and subsequently inverted, but the repeated 

 occurrence of such under-polishing and the finding of it nowhere but at the 

 bottom, would seem to indicate that it was caused by sliding over the surface 

 below. Furthermore, some of the blocks, while being shoved along, appear to 

 have tilted upward in front, and as a result were rounded off at the heel. Much 

 of the rock is thick-bedded and very compact. Other portions are softer, disin- 

 tegrate very easily, are stained brown by iron oxide, and are composed mainly of 

 crinoid fragments. The harder rock contains various species of corals and 

 brachiopods, and occasionally the trilobites Calymene niagarensis and IlUinus day- 

 tonensis. 



Large bowlders of this limestone are found for a mile and more south and 

 southwest from the main moraine. All must have been removed from a point 

 eight, ten or twelve miles north. The fine exposure of striated bed-rock at 

 Thistlethwaite's pond, two miles to the north, has the strife pointing south 2G° 

 west, which is very nearly in line with this morainal deposit. 



