614 GEOLOGY OF OHIO. 



outside of the county limits, but there are several summits within the 

 boundaries that would vary but very little from these figures : 



Feet. 



Fort Hill, above tide water „... 1285.5 



Byington* (railroad grade) above tide water 672 



Latham,* " 1 631.0 



Hill south-east of Latham, " 1224.0 



Shepherd's Mountain, between Cynthiana, and Latham (by barom- 

 eter), above tide water 1170.0 



Scioto bottoms at Jasper, above tide water 566.0 



Low water of Scioto at Jasper, " 533.2 



Jasper Knob, " 1193.6 



Painter's Knob, " 1196.5 



Piketon* (railroad grade at depot), above tide water 578.0 



Riley's Mountain, Jackson township, above low water of Scioto (about) 575.0 



" above tide water (about) 1150.0 



Low water of Scioto on north line of county, above tide water (about) 575.0 

 Low water of Scioto on south line of county, above tide water (about) 500.0 



A range of about eight hundred feet is thus shown to exist between 

 the lowest and the highest land of the county. The greatest vertical 

 range in any one neighborhood, however, as has been already intimated, 

 is found in the hills bordering the Scioto valley. The summits near 

 Jasper — Painter's Knob and Jasper Knob — which lie within two or three 

 miles of the Scioto, rise to a height of six hundred and thirty-three and 

 six hundred and thirty-one feet respectively above low-water mark. 



II. GEOLOGICAL STRUCTURE. 



The geological range of the county exceeds the vertical range above 

 named by at least fifty per cent. In other words, the aggregate thick- 

 ness of the different strata shown in the county is not less than twelve 

 hundred feet, the difference between these figures and the vertical range 

 above named being accounted for by the dip that prevails. 



The appended diagram represents the general composition of the geo- 

 logical series of Pike county. It will be observed that the scale is exten- 

 sive, not only in absolute thickness but in the variety of formations 

 comprehended within it. It is scarcely inferior in either respect to that 

 of any county in the State. (Figure 1.) 



A brief description of the different members of the series will now be 

 given. 



1. The lowest rock, geologically speaking, in Pike county, is found 

 upon its western border. At a few points in the deeper valleys of this 

 portion of the county, and principally in the valleys of the Sunnsh and 



