\ 
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 volime 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. 
Ceesar’s Creek flows in a much shallower trough than any of those 
