ALUM SHALE. 155 



Staiths, is somewhat peculiar. It does not coincide with one or more of 

 the cross veins, so as to make the fracture nearly vertical, but forms an 

 irregular diagonal line, making an angle of about 50 degrees with the 

 scar. The slope, or inclined plane, formed by the fracture, descends 

 towards the west ; and, as is usual in such breaks, the strata have sunk 

 on that side. The quantity of the subsidence is about 30 feet; but in 

 some parts, where there is a double fracture, the angular pieces in the; 

 middle have sunk only a few feet. The Kettleness or ironstone bands, 

 appearing here, make it easy to observe the extent of the fracture. 

 The same remark applies to another diagonal break, about 100 yards 

 further west, where the strata have sunk about 6 feet, on the same 

 side of the fracture. A little nearer the village, at the spot where the 

 Staiths beds begin to appear, there is a vertical break of greater 

 magnitude than either of these ; but the subsidence is in the contrary 

 direction, the Kettleness bands, and the coarse shale beneath them, 

 having sunk down, while the Staiths or sandstone beds abruptly rise 

 up. This rise seems to be greater than the amount of the subsidence 

 at both the breaks now mentioned. The vale of Dalehouse bears 

 marks of the irregularities, occasioned by these convulsions in the 

 strata. 



From Staiths the strata rise in an unbroken series to Boulby, the 

 sandstone bands gradually ascending, while the beds or courses of the 

 lowest shale rise up below, and the upper strata, which had disappear- 

 ed beyond Staiths, successively resume their stations above, as the 

 height of the cliff increases. 



At Boulby we arrive at what may be called the back part of the 

 aluminous strata; for as these strata have their general dip towards 

 the south, and the cliffs there begin to run directly to the west, we 

 seem to be behind the strata, in following their course in that direction. 



The beds of the Boulby series proceed to the west by Rockclifl', 

 where the Lofthouse alum works are carried on, maintaining their 



