86 T. M. HILLS 



At Waverly the top of the CHnton is 310 feet below sea level, 

 and the top of the crystalline rocks, 2,730 feet. The interval 

 between is 2,420 feet. If at Wheeling the interval is the same, the 

 crystalline rocks would be found at 8,198 feet ( = 5,778 + 2,420). 

 Add 1,000 feet for the strata above sea level, and the estimate is 

 brought to 9,198 feet. This figure does not include the increase 

 in the interval between the top of the Clinton and the top of 

 the Trenton found along the northern part of the state, which was 

 21 feet per mile. Addition for such thickening would add 2,520 

 feet, bringing the total to 12,028 feet. 



The north and south line of wells. — This row of wells is practically 

 at right angles to the other two. 



At Norwalk the Trenton was reached 1,945 feet below sea level. 

 In Jefferson Township, Jackson County, it was found at 2,885 ^^^t, 

 a difference of 940 feet in 162 miles, a decline of 5 .8 feet per mile. 

 If this decline continues southward to the Ohio River, twenty-five 

 miles farther, the Trenton would be found there 3,030 feet below 

 sea level. The Trenton (top) -to-crystalline interval of 1,220 feet, 

 found at Waverly, would place the bottom of the sedimentary 

 rocks 4,250 feet below sea level. Add a thousand feet for strata 

 above sea level, as in the previous cases, and we have 5,250 feet for 

 the thickness of strata above the crystalline rocks at the Ohio 

 River, near Ironton. 



Summary. — From the northern line of wells the sedimentary 

 strata of northeastern Ohio are estimated to be nearly 9,000 feet, 

 from those of central Ohio to be over 12,000 feet in the eastern part 

 of the state, and in southern Ohio to be more than 5,000 feet thick. 



Wells along other lines give results of the same order of magni- 

 tude, the same assum"ptions concerning the interval between the 

 top of the Trenton and the crystalline rocks being made. Since the 

 post-Trenton strata thicken toward the Appalachian trough, either 

 by the increase in the thickness of the formations themselves, or 

 the introduction of new formations, it is reasonable to suppose 

 that the pre-Trenton sediments do the same, so that the results 

 obtained are probably underestimates rather than overestimates. 



The presence of the Cincinnati Arch in the southwestern part of 

 the state adds so many complicating features that it does not now 

 seem advisable to attempt an estimate for this part of the state. 



