148 KANSAS ACADEMY OF SCIENCE. 
wood is often fossilized in flowing streams, leaves are almost never preserved 
under such conditions. In fact, it has almost become a paleobotanical axiom 
that conditions which preserved leaves did not preserve wood, and vice versa. 
The theory that these deposits represent a river-bed seems strengthened by the 
fact that several exposures are found in a line extending northeast and southwest 
on both sides of the Platte, while ‘‘ peanut rock”’ is not known in the group out- 
side of the locality just described. 
ECONOMIC PHASE, 
INTRODUCTION, 
The region of Dakota outcrops is by no means the most fertile in the states in 
which the group is located. The reasons for this fact are several. The country 
itself is usually too rocky to admit of cultivation, except in the valleys. Again, 
the soil is often rather light, owing to the presence of so large an amount of sand. 
The cultivated fields on the slopes wash badly, and in many cases have been per- 
mitted to revert to their original condition of grass-covered prairie. Asa grazing 
country it has no superior in the West. 
The rocks of the Dakota group, however, furnish a variety of products of 
economic value. These are distributed throughout the entire region, and are in 
many places a source of a very considerable income. These products will be dis- 
cussed in the following order: Building stone, clays, coal, sand and gravel. 
More than ordinary importance will be attached to these products when it is re- 
membered that in a prairie country, such as is occupied by the Dakota, materials 
of this character are comparatively rare. In not a few instances the Dakota is 
the only rock found. In such regions its products are consequently greatly en- 
hanced. 
BUILDING STONE. 
The sandstone ledges so common. in the Dakota are quarried in numerous lo- 
calities in both Kansas and Nebraska. Nevertheless, in proportion to the 
amount of available material the Dakota is used to only a limited extent. The 
reasons for this are several. Of these, but two will be discussed in this connec- 
tion. 
First. As arule the Dakota sandstone is not desirable building material. 
Representing all degrees of hardness from the very hard clay ironstone and 
quartzite-like rock, which is so hard as to turn the edge of the best tools, to the 
soft sand scarcely cemented together, the stone is either too hard to be dressed 
or too soft to resist weathering. Another objection is the absence of even frac- 
ture in the stone. Most of the ledges are cross-bedded, and, in quarrying, it 
is almost impossible to obtain anything like symmetrical blocks, the bedding 
plane being at all sorts of angles except right angles. Again, the color of the 
stone is often urged as an objection to its use for building purposes. The amount 
of iron in the various ledges even in the same quarry is rarely aonstant, and the 
irregular streaks and blotches of brown, red and yellow in the walls of buildings 
present anything but an artistic effect. 
Second. With exception of the southern Kansas region and the Missouri 
locality, there is scarcely a place in the two states where either the Carbonif- 
erous, Permian, or Benton limestones do not outcrop within a few miles. Usually 
it is but a short distance to quarries of one or both of these formations, yielding 
excellent building stone. As the limestone is more easily worked, is more dura- 
ble, and presents a more artistic appearance than the sandstone, it is often hauled 
within Dakota areas and even past quarries of Dakota sandstone. This may be 
observed in Cloud and Washington counties, Kansas, and Jefferson county, Ne- 
braska. 
