402 
The Ohio Naturalist. 
[Vol. IX, No. 2, 
alluvium, but usually the layer of cherty clay is quite thin, and 
the rock is exposed in roadways, railroad cuts and brook beds. 
The terrace front is steep and practically continuous rock outcrop. 
The bluff to the east of the terrace contains Ohio shale which 
has been seen in several exposures, and below it the Olentangv, 
not exposed, but the drift cover above the shale is thick. 
In some places, this terrace consists of two steps more or less 
definitely separated by a little scarp. There is rarely any flood 
plain below it before the river. It consists of Delaware and 
Columbus limestone, the former becoming verv thin and finally 
wanting at the south end. 
The most important cultural aspect of the terrace, no doubt, 
is the opportunity it affords for quarrying the limestone. The 
terrace front has been opened nearly its whole length, and one 
considerable quarry has been started in its top. The old Smith 
and Price quarry, several little old ones, and the present Casparis 
and at least one other small quarry are to be found in the terrace. 
Part of the terrace top is under cultivation every year, and a 
small portion is devoted to golf links. The Pennsylvania rail¬ 
road finds on it an easy grade from the flood plain in West 
Columbus up to its bridge at Marble Cliff and across to the 
undissected upland on the west side. 
Opposite the west end of Fifth Avenue, is a low rock terrace, 
the present flood plain 400-500 feet wide and three-fourths mile 
long. It stands about 15 feet above the river and bears much 
alluvium especially along its water front so that rock is rarelv 
exposed. 
Farther south and on the west side of the Scioto along the 
big turn toward the east, occurs the most southern rock terrace 
of this river. It is more than a half mile in length, a hundred 
yards in width, and stands 20 feet or more above the river. It 
has been so many times opened for quarrying and modified by 
erosion that details of its surface form are difficult to obtain. The 
T. and O. C. railroad swings across it, as also does the highway. 
A few more rock terraces were found along the Big Darby. 
The first is two miles south of Georgesville on the west side, and 
is about one-fourth by one-eighth mile in size with its top 20-25 
feet above the river. This is the only one along the Darby 
creek that is far above the water. 
For two miles south of the intersection of Big Darby with the 
Columbus and Springfield electric line, a number of miniature 
rock terraces occur, rising 5-20 feet above the water. This 
stream has cut thru the drift mantle, but has only begun here and 
there to cut into rock, hence, it is in a much less advanced stage 
of terrace development than the two larger rivers. Its terraces 
are not large, and are never far above the Avater; but it seems 
probable that a time will come when the Big Darby will have so 
