9 
DETAILED DESCRIPTION OF TYPICAL VEIN. 37 
to about 20 inches. Distortion and fracture of the strata or vein walls 
have occurred. There is local swelling of the earthy bands in the coal 
in proximity to the vein. Vein material is thrust in between the laminee 
of the coal. The clay-vein occupies a rent or fissure in the Coal Meas- 
ures. The “cleat” or vertical cleavage 
of the coal is twisted and deformed— 
“curled,” as the miner terms it—on one 
or both sides of the vein, and often toa 
distance of many feet, making the coal 
exceedingly hard and comparatively 
worthless. Cracks occur in the vein 
walls, more or less filled with clay, 
pyrites, etcetera. The dip of the coal 
is slightly altered on one or both sides. 
The vein stuff is fragmentary and mixed | 
in character, and consists of small bits 
of shale of varying degrees of hardness, 
texture, color, etcetera; of sandstones 
stones and grits; of lumps of whitish 
and yellowish limestone, often quite soft; of chips of chert, ironstone, 
coal, etcetera ; of flakes of mica; quartz and other hard grains; with very 
much clayey material ; with pyrite and marcasite, in crystals and streaks ; 
and nodular concretions of the various fragments; those of pale gray 
shale seem to predominate. 
The aspect of the vein stuff, when of a decidedly fragmentary or brec- 
ciated character, as viewed in the direction of the vein walls, is somewhat 
Figure 1.— Vertical Section of Ordinary Clay- 
vein. 
One-fiftieth natural size. 
ti 
/ 
Figure 2.— Vein Stuff. Figure 3.—Vein Stuff. 
Natural size. Natural size. 
roughly shown in figure 2, while the same material, viewed in the direc- 
tion of the clay-vein, is indicated in figure 8, which exhibits a decidedly 
