Mr. With am on the Greenstone Dyke, fyc. 



345 



In illustration of the complicated action of these faults, I annex a short 

 section of the Auckland Coal district in the county of Durham, from which 

 will be apparent the amazing force which must have been in operation 

 when they were formed ; the surface of the earth must have been agitated 

 like that of the sea, and by a force which there can be no doubt was vol- 

 canic, from the identity of the effects produced on a small scale at the pre- 

 sent day. 



PIT 



