Whiteway Head, from a drawing by Mr. B. W. Evans (Aymestry Limestone, beds dipping to the S.E.). 



CHAPTER XX. 

 SILURIAN SYSTEM {continued). 



Joints of the Silurian Rocks. — Landslips. — Wells. — Agricultural characters of the 



Silurian System. 



Jointed structure of the Silurian Rocks. 



The subject of joints has engaged the attention of many geologists. Even in the 

 early days of the science, De Saussure observed them in the rocks of the Alps, and the 

 phenomenon was not unnoticed even by our old native writers. Morton, for instance, 

 in his Natural History of Northamptonshire, describes long joints or fissures, as di- 

 stinguished from "gutters, gulf joints, &c," and distinctly points out their great use 

 to the quarriers, p. 124. to 136. In recent times MacCulloch attempted to give an 

 explanation of the joints in granite founded upon crystalline laws. Mr. Enys, followed 

 by Mr. Fox, described the granite joints of Cornwall, and showed that they had given 

 directions. (Phil. Mag. vol. ii. Third Series, p. 321 .) Dr. Boase has written much upon 



