EXPLANATION OF PLATE 67. 107 



The inclination of this hed directs its course towards 

 the Fault H, where its progress is intercepted by the 

 dislocated edge of the Clay bed b', and a spring is 

 formed at the point f. Springs originating in causes 

 of this kind are of very frequent occurrence, and are 

 easily recognised in cliff's 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. 418, 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. 419. 

 (Hoffmann.) • 



Explanation of Letters referred to in this Figure. 



a. Keuper. 



b. Muschelkalk 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, 1136 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. 



