FAULTS IN THE COAL-MEASURES. 



68" 



of erupted trap which has occasioned the dislocation, 

 rises to the surface, and forms the summit of Barrow Hill ; 

 an elevation of about 600 feet. The displacements of the 

 strata on each side of the volcanic rock have produced two 

 lines of fault : and the coal in contact with the igneous 

 rock, as is usual under such circumstances, is charred, and 

 deprived of its bituminous quality. 



In the principal fault, the coal-beds are rent asunder to 

 an extent of 140 yards ; and in the part represented in the 

 sketch (Lign. 153), the erupted mass (h) has upcast the 

 strata on the south-east ninety yards (a) ; the sides of 

 the fissure being inclined from eighty to ninety degrees ; 

 thus the strata (<z, d,) which were originally continuous, 



Trap. 



Lign. 153.— Section of a Fault in the Dudley Coal-field, near 

 Barrow Hill. , 



a, d, Carboniferous strata; the black line denotes the main bed of coal; b, Intruded 

 Trap ; c, the upward twist of the bed of coal d, where in contact with the Trap- 

 dike. 



and horizontal, have been separated, and the edges of the 

 lower bed of coal twisted upwards, as is shown at c, by the 

 intruded trap. These carboniferous strata are super- 

 imposed on red conglomerate. We shall have again 

 occasion to notice the displacements in the Dudley Coal- 



