96 
there are two out-crops of the red marl at the latter place. 
The places through this line of country where gypsum has 
been excavated, are : — 1. Half a mile west of Oldcoats, on 
the Firbeck road. 2. The mill dam, three quarters of a 
mile west of Tickhill. 3. Brick pits, west of Wadworth. 
4. South-west end of Cusworth Park. 5. West side of 
Campsall and Clay flatts. 6. The west side of the village 
of Askern. 7. The south-east end of Norton. 8. On both 
sides of the AVent below Little Smeaton. 9. In Womersley 
belt, half a mile south and west of the house. 10. Pits on 
the west side of Grove Hall. 11. In the cutting of the York 
and North Midland Railway, at Brotherton. 12. Plasterpit 
Hill, near Fairburne. 
3. The geographical extent of the Yellow Limestone is 
well known and requires little notice. Its precipitous es- 
carpment defines its western boundary, and the beds last 
described its eastern one. Its great western terrace extends 
from Glass Houghton, near the Aire and Calder, by Ponte- 
fract to Wentbridge, at both of which places the whole 
thickness of the bed has suffered deep denudations by the 
action of a large body of waters bearing with them pebbles 
from the carboniferous series. From the latter place it ex- 
tends by Upton Beacon, Hooton Pagnell, Hickleton, and 
Melton Park to Cadeby. Down the course of the Don it 
has been denuded to a considerable extent, Conisbrough 
Castle, standing on an outlying mass of rock which remains 
as a monument of the disrupting forces which excavated the 
valley of the Don. The limestone from hence passes by 
Micklebring, Maltby, and is then carried as far east as 
near Sandbeck park, a little to the west of which the lime- 
stone is cut through, and the subjacent coal strata are to be 
approached at no great depth from the surface ; and there 
is no doubt that the estates of Lord Scarborough here cover 
