CHAPTER LXXTTI. 
REPORT OF THE GEOLOGY OF ES Eells COUNTY. 
BY EDWARD‘ ORTON, ASSISTANT GHOLOGIST. 
Preble county is bounded on the north by Darke, on. the-east by Mont- 
gomery, and on the south by Butler county. Its western boundary is the 
Indiana line. | 
The altitudes of a few points im 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 Pomeroy, 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. All are counted 
above low-water of the Ohio at Cincinnati, and to be changed into alti- 
tudes above the sea, must be increased by four hundred and thirty-two feet. 
The elevations farnished by Mr. Pomeroy assume Greenville, Darke county, 
to be (railroad grade at depot) five hundred and seventy-six feet above low- 
water at Cincinnati. Different railroad surveys, however, give different 
figures for this elevation, the variation between them amounting to seven- 
seen feet. This element of uncertainty can not be eliminated here: 
FEET, 
1. Eaton (sili of court-house)...---..-.. pia ie Ge eae Aeatereleratatole fans iar alates 612 
2. Camden (general level of town) ......---..--.-.--.-- He SN A07 
3. County line in Section 32, Sonora township......-----.-- RL wate Tena he 60E 
4, North-west corner, Israel township....-.-.--..---e2+ ---e0+ --e- Reta ae 656: 
5. Summit of Blue Limestone, Halderman’s mill.......2.0.2..-2c-.-0ee- 515 
6. South line of eounty in Section 33, Gratis township ..-..-.--.. ra siete meses 586 
Pee WIN CHOSbER 2.5 2 ee sa oi oo oc an re eerie erat ore saat were 425 
8. West Alexandria (valley of Twim Creek)...-....--..------------ oe ee 427 
9. Lewisburg ef FS NAP Ce Ss Pha disie ee me Pole Ge ese 49S 
AOS Sonora (ratlroadigrade)iessayneese ee aiecnieontce ce cictcininer te settane aistetwnisiaiste 544 
Extreme south-east corner, Lanier township, valley of Twin, say.---...--.. 300! 
| Valley of Seven Mile, on county line, say.--...---...------ ewe coed Secombe Se 325 
Ridge passing through Monroe, Jackson, ete., say--.-.-- 100 boeabn Seog ances GAS 
The vertical range, then, of the county is about three hundred and 
fifty feet. The geological range, as far as the bedded rocks are concerned; 
ig somewhat less. | 
