Drift. 1 1 



composed in very great part of limestone. The lower gravel beds, 

 therefore, carry the undercurrent of the Ohio, or the waters of 

 the ancient stream, while the modern drift and upper terraces carry 

 the waters o^ our limestone hills. When the ancient drift is pene- 

 trated, where it is not too remote from the Ohio River, we obtain 

 filtered Ohio River water. 



The general topographical features of the immediate vicinity of 

 Cincinnati are quite familiar; yet there are very few who have 

 studied in detail the forms and positions of the surrounding hills 

 and valleys. The general direction of the Ohio River is south of 

 west, its channel being about four hundred feet below the level of 

 the plateau on either side. From the North it is joined above the 

 city by the Little Miami, and about twenty miles below the city by 

 the Great Miami, the direction of each being west of south, each 

 passing through a well-defined valley corresponding in depth to 

 that of the principal water-course. Directly opposite the city the 

 Ohio is joined by the Licking River, flowing in a northwesterly 

 direction. These facts are generally known; but the valleys of the 

 minor tributaries, their forms, directions and connections, as well 

 as the windings of the greater and lesser valleys, with their coves 

 and terraces, are known only to the special topographical student. 

 For example. Mill Creek, joining the Ohio from tl e North at Cin- 

 cinnati, is a minor tributary, yet its valley is of such a nature as to 

 furnish a satisfactory reason for building a great city where Cincin- 

 nati now stands rather than at any other point on the north bank 

 of the Ohio within the limits of the Stale. 



Any attempt to estimate the number of years which the lime- 

 stone plateau, which we term the "Cincinnati group," has been 

 exposed to the eroding action of the subaerial agents would be 

 puerile. Could the time be determined, and the number of years 

 written in figures, it is entirely probable that the magnitude 

 expressed would be altogether incomprehensible to our minds. 

 The accompanying diagrams show, in geological epochs or periods, 

 the comparative age of the rocks in this locality and how near 

 they lie to the base of the Geological Column, as known to us.-i- 



An examination of these sections at once reveals the fact that 

 this formation is of great age ; and — when we reflect on the gradual 

 manner in which sedimentary rocks are formed; that the "Cincin- 

 nati Anticlinal" is flanked by formations aggregating miles in 



•■■See Sections of Rocks, " Dana s Manual of Geolnoy, ' page 131; and 

 Volume I. of " Geological Survey of Ohiu," page 88. 



