77 
GENERAL STRATIGRAPHY OF THE REGION. 
i 
Upper A\ ashington coal. Above the black bituminous shale is from 
5 to 20 feet of gray laminated sandstone, reaching within a few 
inches of the Donley limestone. 
DONLEY LIMESTONE. 
h or the most widespread and uniform limestone in the Greene 
formation throughout the Claysville quadrangle the name Donley is 
here proposed. It is from 18 to 45 feet above the bottom of the 
formation, and in this quadrangle is invariably present where its 
horizon comes to the surface. In the vicinity of Donley, Donegal 
Township, a typical section shows this limestone in three or four 
layers, having a total thickness of 5 or 6 feet. The characteristic 
feature is its dark, rusty, lichen-covered surface when exposed to 
weathering. The limestone is very hard and tough, and fractures 
unevenly with a dark steel-gray to almost black color, having a verv 
coarse grain and showing numerous calcite crystals. The bed is also 
distinguished bv its peculiar jointing, which has a striking resem¬ 
blance to that of dry mud, the blocks being irregular in shape and 
from 1 to 3 feet in diameter. The joints are usually very distinct, 
many of them being from 1 to 3 inches wide, filled with dark ’red 
clay. 
SPARTA COAL AND ASSOCIATED ROCKS. 
Above the Donley limestone is a sandstone with a thickness of 15 
to 20 feet, usually of a light-gray color and laminated, but in places 
consisting of several massive ledges. Above this is a few feet of 
reddish shale which reaches to the Sparta coal, the most important 
coal bed of the Greene formation. The coal is from 0 inches to 3 
feet thick. It attains its greatest thickness in the vicinity of East 
Finley, where it was once mined, though all banks have long since 
been abandoned. Those who have used it say that the best of it is 
somewhat rusty in color, makes a hot fire, and burns to a small 
white ash. 
PROSPERITY LIMESTONE. 
The next distinctive member above the Sparta coal is a rusty- 
yellow limestone, having a maximum thickness of 10 or 12 feet, 
which is here named the Prosperity limestone, from the village of 
that name in Morris Township. The top layers are in places light 
bluish, fracturing irregularly with a dark-gray to rusty-black color, 
r nd very coarse grained. The other layers are dark gray to buff 
on fracturing. This limestone is fairly persistent over the southern 
half of the Claysville quadrangle, being present on all the hillsides 
in the vicinity of Pleasant Grove. Its heaviest outcrop is northeast 
of Pleasant Grove, along the top of the ridge between East Finley 
and South Franklin townships. 
