WARREN COUNTY. 397 
this report shows two groups of areas in the county, as has been already 
stated, viz., the uplands and the alluvial lands. This latter division de- 
mands a brief description at this point. The valley in which the Great 
Miami now flows, and the two south-eastern branches of this valley that 
were occupied by the river in some earlier period of its history, together 
- contain not less than seventy-five square miles. This area constitutes one 
of the finest agricultural districts in the State. Land embracing a greater 
number of advantages, in fact, is scarcely to be found anywhere. The 
-fellowing points are to be observed : 
1. The bedded rock has been cut out to a greater depth than existing 
agencies can account for throughout most of this area. The rocky floor 
is very seldom laid bare by the river, and it is as seldom struck in any 
excavations or borings that are made in the valley. 
2. The valley is filled with immense accumulations of gravel and 
bowlders. These gravel-beds undoubtedly overlie deposits of bowlder 
clay in many parts of the valley. Indeed these deposits are occasionally, 
though rarely, struck in wells and similar excavations; and sometimes 
they even approach very near the surface. The gravel is of various 
sorts and sizes, and indicates various degrees of strength in the currents 
that have transported it, Large quantifies of sand are distributed 
through it. In composition, it is principally limestone, thus agreeing 
with the pebbles and bowlders that fill the Drift clays of the country, 
but, unlike the true Drift pebbles, it has lost the marks of the previous 
stage in its history, viz., the shaping which it received under the glacial 
sheet. Its pebbles no longer show the polish and striation due to this 
stage, but, on the other hand, bear unmistakable marks of having been 
fashioned in running water. 
3. The gravel beds are in all cases covered with considerable deposits 
of loam and sand, which form the present surfaces of the valley. These 
_ deposits are arranged in three natural and well marked divisions, viz., 
the first bottoms, the second bottoms, and the gravel terraces, sometimes called 
the third bottoms. Of this series, contrary to the general order in geology, 
the lowest member, viz., the first bottoms, is the newest, and the highest 
member viz., the gravel terraces, is the oldest. In other words, the first 
and second bottoms do not extend beneath the gravel terraces, and con- 
sequently do not result from the denudation of portions of the valley. 
The gravel terraces are at least one hundred feet above low water of the 
river now. They are generally left in small and isolated fragments on 
the margins of the valley, but sometimes they are found to hold consid- 
erable areas. In the vicinity of the village of Trenton they can be seen 
