ROSS COUNTY. 651 



The remainder of the series consists, for three hundred feet, of beds of 

 shale, holding great quantities of flattish concretions, which contain a 

 clayey center, covered with a thin blossom of iron ore. These concre- 

 tions vary in size from an inch to a foot in their largest diameter, and are 

 every where throughout this region characteristic of the Upper Waverly. 

 Thin courses of a light brown sandstone often find place, but there is 

 scarcely the possibility of a quarry in this whole interval. 



But few fossils are found in all of the series thus far traversed. The 

 singular form, Spirophyton, is met with quite frequently through several 

 hundred feet, but it is only at a height of three hundred and fifty feet 

 to three hundred and seventy-five feet above the Waverly black slate 

 that a stratum comes in that may be called highly fossiliferous. 



It is shown in very many sections in the county, but the best exposure 

 of it yet noted occurs on the south side of Sugar Loaf Mountain, about 

 one hundred feet below the summit. An opening has been made here 

 for a quarry. Attention was first called to this point by Mr. J. H. Poe, 

 of Chillicothe. The usual line of Waverly fossils is to be seen here — 

 remains of crinoids, bryozoans, and bivalve shells. 



The uppermost seventy -five feet of Mt. Logan, and also of Rattlesnake 

 Knob, show the same stratum, as do also all the high lands in the north- 

 eastern corner of the county, especially in Colerain township. It will 

 also be remembered that the high ground of Pike county shows, in many 

 places, this same fossiliferous formation. 



Comparatively little valuable quarry stone is found above the Buena 

 Vista beds, but there is hardly any part of the county that does not 

 possess a fair neighborhood supply within easy reach. 



The geological scale of the county has now been briefly reviewed, as 

 far at least as its bedded rocks are concerned, and the chief points of 

 interest in it have been touched upon. Its Drift formations must be 

 discussed with equal brevity. 



II. DEIFT DEPOSITS. 



The Drift deposits of Ross county are much more interesting and im- 

 portant than are those of Pike county, or of any of the districts to the 

 southward. A principal point of interest is found in the fact that the 

 boundary which separates the regions, every part of which has been 

 covered by the Drift formation, from those in which the high lands, at 

 least, were never occupied by the glacial sheet, passes through the 

 northern and central townships of the county. In other words, a part 

 of the county agrees in its later geological history with the northern 

 part of the State and of the continent, while the larger portion takes its 



