1865.] 



WALLACE PLOS FEEBI. 



(419 



to a considerable amount of decomposition ; for a great portion of 

 them had a corroded appearance. It seemed, however, that before 

 the decomposition commenced, the points of the stalactites had been 

 violently broken off. Some of the corroded lime was thinly covered 

 with a fine clay ; and upon nearly the whole of it beautiful crystals 

 of arragonite were forming, and in some places the clay was incor- 

 porated half an inch or so below the crystals. I may observe that 

 no stalagmites were formed on the bottom of the cavern to correspond 

 with these stalactites ; or if they had once been there, they must have 

 been entirely dissolved without leaving any trace of their existence. 



Fig. 2. — SJcetch of a horizontal stem of Arragonite in the Dufton 

 Fell Mine. 



It is scarcely necessary to point out the impossibility of stalactites 

 being formed in a cavern filled with water. The arragonite must 

 therefore have grown in some kind of air or gas. The fact of its 

 crystals covering a stalactite in the course of formation with a cor- 

 responding stalagmite on the floor of the cavern sets this point en" 

 tirely at rest. Indeed a glance into the cavern would have been 

 sufficient to convince a reasonable mind that the arragordte was 

 formed after the water was drained from the large joint. 



Fig. 3. — BJcetch of a bent stem of Arragonite in the Dufton Fell Mine. 



But if the arragonite could not have been formed in water, as in 

 the Silver Band cavern, so also in this cavern it was impossible for 



