After disturbance. 



a. Lower New Red Sandstone. b. Coal Measures with thick Coal. c. Lower Coal and Ironstone. 



d. Silurian Rocks. e. Trap. 



It was the desire to understand the anomalous protrusion of the Silurian and trap 

 rocks, which induced me to examine the district, and in acquiring a knowledge of their 

 position, I have necessarily become acquainted to some extent with the overlying car- 

 boniferous strata. 



That portion of the field, of which Dudley may be called the centre, and which ex- 

 tends northwards to Wednesbury and Bilston, and southwards to near Hales Owen, is 

 filled with the thickest masses of mineral matter, constituting two great divisions, in 

 the upper of which is the celebrated 10 yard coal; in the lower, seams of less thick- 

 ness, alternating with beds of ironstone. (See Map 1 .) To the north, the overlying 

 or thick coal crops out, and the lower or ironstone measures rise to the surface, 

 and occupy the district between the towns of Wolverhampton and Wallsall. Though 

 varying much in their mineral contents, they probably range through all the carbona- 

 ceous tract, extending by Wednesfield Heath, Bloxwich, and Essington to Cannock 

 Chace and Beverton, near Badgeley 2 . In like manner, and at the south-western end 

 of the tract, near Stourbridge, the lower carboniferous strata again rise for a small 



1 I may here remark, that in the map the portion of the district which contains both the thick coal and the 

 lower measures is marked by a deeper tint of black. 



2 I have not well examined this north-eastern tract beyond the Lanesfield and Monmore collieries. The 

 continuation of this coal tract, extending from Cannock Chace to Beverton, lies indeed, beyond the limits of 

 the published sheets of the Ordnance Survey ; which work, as before explained, is the foundation of the ac- 

 companying map. (See Introduction.) 



