660 GEOLOGY OF OHIO. 



report, and upon which the alluvial valleys of the county are also indi- 

 cated, serves to bring out this point very distinctly. 



It will be remembered that in the report upon Clarke county an older 

 valley of the Great Miami River is shown to exist, connecting its present 

 valley with that of Mad River. In other words, the junction of these 

 streams was effected below Springfield, instead of taking place at Dayton, 

 as at present. And thus it seems probable that the valley now under 

 consideration, viz., the valley of Beaver Creek, was formerly occupied by 

 the waters of the Great Miami after they had been re-enforced by the 

 whole volume of Mad River. With such an origin, the present dimen- 

 sions of the valley are easy to be understood. 



The valley of the Little Miami, in Greene county, consists of two well- 

 marked portions, the lowermost of which has been cut out of the shales 

 and limestone of the Cincinnati series, while in the upper portion the 

 river has been obliged to hew its way/ through the massive courses of the 

 cliff limestone. The lower valley is, therefore, deep and capacious, while 

 the upper part consists of a narrow gorge, bounded by precipitous walls. 

 The first of the above-named divisions constitutes one of the most valu- 

 ble tracts of the county, in an agricultural point of view ; the second has 

 no such economical applications, aside from the water-power which the 

 river here furnishes in large amount, but which has not yet been utilized 

 to any great degree. Indeed, it returns but little in dollars and cents, 

 but it furnishes the most picturesque and attractive scenery not only of 

 the county but of all the region around. There is but one point in all 

 south-western Ohio where more striking scenery is shown than that fur- 

 nished by the gorge of the Little Miami between Grinnell's Mills and 

 Clifton. The limestone is cut down to a depth of from sixty to eighty 

 feet, while the valley never exceeds a few hundred feet in breadth; and 

 at Clifton it is contracted to a score or two of feet, being sometimes actu- 

 ally four times as deep as it is wide. The geological elements that are 

 shown in the valley will be treated of in the succeeding pages of this re- 

 port, and the influence of each upon the proportions which it assumes 

 will be duly considered. 



Several of the more prominent tributaries of the river exhibit features 

 quite similar to those last described. The valley of Massie's Creek, below 

 Cedarville, presents scenery almost as striking as that furnished by the 

 Little Miami at Clifton. Clark's Run, near the south line of Miami 

 township, shows another of these deep gorges, while the beautiful glen 

 at Yellow Springs, which has had precisely such an origin, is known to 

 thousands of people in south-western Ohio. 



Caesar's Creek flows in a much shallower trough than any of those 



