- Fieure 23.—Section of Clay-vein in the ‘Little?’ Coal 
D4 Ww.s. GRESLEY—CLAY-VEINS INTERSECTING COAL MEASURES. 
wall of this fault which the curved and cracked strata suggest was the 
cause of the open break in the coal. 
Figure 23 represents a section exposed in the workings of the “ Little” 
coal at Donisthorpe, Derbyshire, at about 650 feet deep. In this case a 
tearing apart of the coal bed, accompanied by about 2} feet of displace- 
ment, has taken place. When the rent was opened, the “horse” of 
shale, a fragment of the roof of 
the seam, fell in and came to rest 
on the under clay. Then the 
ieee composed mass of rock debris 
ia filled up the rest of the opening 
to a height extending beyond the 
roof of the excavation. 
Figure 24 illustrates a section - 
exposed in a tunnel or drift at 
Moira, in Leicestershire, at a depth 
of about 1,050 feet, at a point 
where a fault of 240 feet throw 
was crossed. From wall to wall the fault filling was about 20 feet wide, 
and carried, near its middle, a large horse-like mass of coal 3 feet thick. 
The rest of the material consisted of angular and crushed fragments of 
a variety of Coal Measure strata, more or less cemented together with 
pyrite, calcite, quartz, etcetera. The character of the contents of this 
deposit make it evident that the fault originally existed in the form of a 
huge gaping rent in the Coal Measures, which remained open long 
of Derbyshire. 
One-fiftieth natural size. 
Figure 24.—Section in a Tunnel at Moira, Leicestershire. 
One-hundredth natural size. 
enough to become filled in the manner shown. The same fault was 
crossed about 1% miles to the northeast of this section in a railway cut. 
Its width there was 12 feet, and angular blocks of coal formed part of 
the more clayey filling. / 
Figure 25 represents a vertical section revealing a remarkably flat vein 
of clay, X X’, intersecting the “ Lount Middle” coal bed at Coleorton, 
< 
