16 
4. Upper slaty limestone. 
5. Red marl seen at Hexthorp. 
The most extensive movements in the earth's crust now 
took place at this period. Professor Phillips says, " Every 
" coal field in these islands is remarkably dislocated by 
" faults, often traversed by trap dykes." . . . One of the 
most remarkable great faults or dislocations yet known in 
the world belongs to this period, viz., the great and continu- 
ous fracture of the earth's crust from Cullercoats, near 
Newcastle, westward along the Tyne valley to Brampton, 
thence southward to Brough, Kirby-Stephen, Dent, and 
Kirby-Lonsdale, a distance of 110 miles. One portion is 
elevated above the other from 1,200 to 4,000 feet. I may 
add that the same disturbance is prolonged southwards to 
near Derby, so that the whole area of the Yorkshire coal 
field is elevated above that of Lancashire 3,000 or 4,000 
feet. Both sides are in fact elevated, but the Yorkshire 
side more so. Other elevations and expansions of the crust 
are seen in particular localities. In the valley of the 
Don, between Rotherham and Sheffield, is an example of 
an enormous fracture. At Keppel's Column is a known 
coal seam called the Park Grate Bed, near the surface ; 
one mile south this same seam, instead of being near 
the surface, is 700 yards deep, so that both the sides 
of the valley being elevated, yet the Wentworth House 
side is raised more so to the before-mentioned amount. 
There is some little dispute among geologists as to 
the exact date of these movements, whether they occurred 
before or after the deposition of the permian system, but 
a study of the geology of the country around Doncaster, 
by Wadworth, Conisbro', &c, will show that the magnesian 
limestone has been greatly disturbed, and that the same 
dislocations range westward, and are connected with 
those of the Don. 
