444 GLANCE AT THE GEOLOGY OF 



the iron. During the formation of the old red, 

 as well as of the new red sandstone, a vast 

 amount of per oxide of iron appears to have been 

 mingled with the waters of the ancient ocean. 

 But still the quantity in the iron mines of Low 

 Furness, is such as to indicate a proximity to the 

 source from whence it originated. It appears to 

 have been thrown up by volcanic action, and then 

 carried, by some means, into the valleys and 

 fissures where it is now found. But whether the 

 iron was injected into the places where it is now 

 met with, through the fissures immediately below, 

 or was first mingled with the waters of the sea, 

 which then flowed through the fissures and ca- 

 verns of limestone, and gradually filled them up 

 with the metallic matter, held partly in solution, 

 as Professor Sedgwick thinks, is difficult to de- 

 termine. The neighbouring district towards the 

 mouth of the Duddon and Black Coomb, show 

 abundance of proofs of having been formerly 

 much disturbed by volcanic agency. 



The upper silurian rocks, which bound the 

 carboniferous limestone, which are merely alluded 

 to as a boundary line, appear to have been elevated 

 before the deposition on their edges of the latter 

 rock. They form the northern part of the dis- 



