CHAPTER LXXII. 

 EEPOET OF THE GEOLOGY OF PREBLE COUNTY, 



B¥ KDWARD OBTCMS, ASSISTANT SEOIXXHST. 



PreHe county is bounded od the north by Darfce, on the east by Mont- 

 gomery, and on the south by Butler cou-nty. Its western boundary is the 

 Indiana line. 



The altitudes of a few points in the county are -given. The first five 

 are taken from Dr. Locke's report of the former Geological Survey of Ohio, 

 and were furnished to him by Col. J. W. Erwin, of Hamilton. For the 

 remainder, the survey is indebted to Phineas Fomeroy, Esq., of Winches- 

 ter, Indiana. They were obtained by him in making a survey for a pro- 

 posed railroad line along the valley of Twin Creek. j^U are counted 

 above low-water of the Ohio at Cincinnati, and to be changed into alti- 

 tudes aboYe the sea, must be increased by four hundred and thirtytwo feet. 

 The elevations furnished by Mr. POmteroy assume Greenville, Darke county, 

 to be (railroad grade at depot) five hundred aind seventy-six feet above low- 

 water at Cincinnati. Dlfierent railroad surveys, howerer, give different 

 figures for this elevation, the variation between them amounting to seven- 

 teen feet. This- element of uncertaittty can not be eliminated here : 



PEBT. 



1. Eaton (aiD of court-house) .... 612 



2. Camden (general level ot to'vru) 407 



3. Coonty line in Section 32, Sonora township 601 



4. North-west corner, I&ra®l townsbip 65& 



5. Summit of Blue Limestone, Haldermau's mill 51& 



6. Sonth line of eounty in Seetion 33, Gratis township , 58& 



7. Wincbester 425 



8. West Alexandria (yaUey of Twin Creek) 427 



9. Lewisbwrg " " 495 



10. So'nora (railroad grade) 544 



Extreme south-east com«r, Lanier township, valley of Twin, say . 350 



Valley of Seven Mile, on county line, say 325 



Eidge passing through Monroe, Jackson, eto^ say , 675 



The vertical rangr, then, of the county is about three hundred and 

 fifty feet. The geological range, as far as the bedded rocks are concerned, 

 is somewhat less. 



