314 Carboniferous Formation of Pennsijlvania — Wasnnith. 
disintegrated rock, etc. A close examination of workings in 
coal mines will convince one, that the coherence of strata in 
many instances is sufficient to permit of the slight bending of 
coal and rock for a greater or less distance, without fracture. 
If for example, the fracture g, _r/, appears as indicated in e, fig. 
3, the dip (hade) of the fracture is in the direction of the dip of 
the strata, but steeper. Such occurrences generally show that 
the part a, e, of the coal bed has not been curved; it resisted 
bending and sinking by the underlying strata, but then by the 
force of gravitation the part e, 6, of the coal bed has slid down 
as indicated by /, b, fig. 3, frequently without bending that 
part of the strata. The fracture always is filled with disinte- 
grated rock, consequently a ''rock-lode," and if the general terms 
"hanging-wall," ''foot-wall," etc., are applied to it, we have a 
fault (disconnection and dislocation), whereby the part of the 
strata on the hanging wall of the fault is in a lower position 
than the part on the foot-wall. Z Such faults are termed "trans- 
verse faults" (fig. 1). If the fracture g' </' appears as indicated 
in h, fig. 3, then the dip of the fracture is contrary to the dip 
of the strata, showing similar effects of the dislocated parts of 
the strata as before indicated by nt, ?, A', and 5, h. Such occur- 
rences are termed "transverse faults with contrary dip." 
Another dislocation is illustrated in fig. 4. The line a, J, 
represents the synclinal axis, not located yet, and c, d, the 
fracture, which is developed for 
^length of more than 1,000 
yards in the Westmoreland 
shaft. The average dip of the 
coal bed in the neighborhood 
of the fracture is about 1 to 2 
degrees and the cross-section 
e, /, fig. 5, approximately would be as indicated. The strike of 
the fracture probably is nearly in the course of the synclinal 
axis, and the part of the strata on the hanging-wall of the frac- 
ture is in a higher position than the part on the foot-wall; the 
portion on the foot-wall of the fault has slid down, thus origin- 
ating a complete and distinct over-lapping of the coal bed of 
about 6 inches; the fracture is about 2 inches wide and it is 
filled with disintegrated coal, probably on account of the 
slight sinking of the strata and because only coal surfaces have 
