Geology 



some 250 feet deep, and on the vertical face on 

 the opposite side of the stream we saw on our left 

 the Carboniferous Limestone, and on our right the 

 Coal Measures, with their two seams of Coal. Between 

 the two lay about 30 feet of crushed and broken 

 "fault rock," the line of the fracture being inclined at 

 an angle of 75 to the right. The Coal Measures were 

 bent upwards near the line of fault, as though torn and 

 frayed against the surface of movement (Fig. 29). 



Having returned to the main stream, and again 



FIG. 29. a, Carboniferous Limestone ; &, Coal Measures ; c, Fault with 



fault-rock. 



crossed the fault, we entered upon a region of magnificent 

 scenery. On either hand the limestones rose terrace 

 above terrace for several hundreds of feet, while the 

 dark openings of numerous caverns were to be seen 

 along the top line of the dazzling white screes which 

 fringed the face of each gigantic step (Plates X. 

 and XI.). 



In several places long vertical rifts or chimneys cut 

 through the terraces ; they were evidently due to the 

 weathering out of some material less resistant than 



the massive limestone beds. So persistent was this 



194 



