EXPLANATION OF PLATE 67. 107 



The inclination of this bed directs its course to- 

 wards the Fault H, where its progress is intercepted 

 by the dislocated edge of the Clay bed h' , and a 

 spring is formed at the point f. Springs originating 

 in causes of this kind are of very frequent occur- 

 rence, and are easily recognized in cliffs upon the 

 sea-shore.''^ In inland districts, the fractures which 

 cause these springs are usually less apparent, and 

 the issues of water often give to the Geologist notice 

 of Faults, of which the form of the surface affords 

 no visible indication. See V. I. p. 560, Note. 

 Fig. 2. Section of the valley of Pyrmont in Westphalia. 

 A cold chalybeate water rises in this valley at d, 

 through broken fragments of New Red Sandstone, 

 filling a fracture which forms the Axis of Elevation 

 of the valley. The strata are elevated unequally 

 on opposite sides of this fracture. See V. I. p. 561. 

 (Hoffmann.) 



Explajiation of Letters referred to in this Figure, 



a. Keuper. 



b. Muschel-kalk or shelly Limestone. 



c. Variegated Sandstone. 



d. Cold chalybeate Springs rising through a fracture on 



the Axis of Elevation of the Valley. 

 M. The Muhlberg, 1107 feet above the sea. 

 B. The Bomberg, 1 136 feet above the sea. 

 P. Pyrmont, 250 feet above the sea. 



Fig. 3. Section reduced from Thomas's survey of the 

 mining district of Cornwall (1819) ; it exhibits 



* Three such cases may be seen on the banks of the Severn near 

 Bristol, in small faults that traverse the low cliff of Red Marl and 

 Lias on the N. E. of the Aust Passage. See Geol. Trans. N. S. 

 Vol. I. Pt. II. PI. 37. 



