418 PKOCEEDINGS OP THE GEOLOGICAL SOCIETY. [April 26, 



-from the sides. As might be expected, the unfilled portion is near 

 the top of the joint. 



The greatest amount of decomposition had taken place at the inter- 

 section of the joint with the east and west vein. At the time when 

 this vein was mineralized its walls in the limestone strata had under- 

 gone a considerable degree of metamorphism, rendering it more sus- 

 ceptible of decomposition than ordinary limestone. Hence at this 

 intersection the joint is of considerable width ; it contained chiefly 

 hydrated peroxide of iron and a little carbonate of lime. I could 

 find no sulphate of barytes, though directly above, in the Tyne Bottom 

 limestone, the vein and 'flats contained very large quantities of this 

 mineral. 



I have said that the joint was cut off by a bed of soft sandstone, 

 which separates the Melmerby Scar limestone and Eobinson's lime- 

 stone. On the north side of the vein a thin post of limestone, how- 

 ever, remained uncut through, upon which the arragonite was formed. 

 Except at the intersection with the vein the joint was generally 

 about 1 foot wide ; here it widened out to about 5 feet ; but towards 

 the north end of the cavern it was not more than 1^ foot wide, and 

 -this space was almost blocked up with a growth of arragonite. 



The sides of the cavern were damp ; but there was sufficient 

 moisture in only two places to form drops, and it was there where 

 the greatest thickness of arrag-onite was formed. At the north end 

 of the cavern the water descended through a small tube in the arra- 

 gonite and formed a stalactite, from the end of which it dropped 

 slowly, and a thin stalagmite (the only one in the cavern) was formed 

 by this di'op on the soft floor. The stalactite was covered with small 

 crystals of arragonite, but there were none upon the stalagmite. 



At the south end of the cavern the moisture had very slowly 

 streamed down a portion of the west end. Here the arragonite was 

 formed at the roof and about 2-| feet down the end and west side ; 

 below, in a narrow strip, the side was encrusted with lime, which 

 was most thickly deposited near the arragonite, and thinned off to 

 nothing before it reached the bottom of the cavern. This incrusta- 

 tion was much discoloured. The most splendidly branched arrago- 

 nite was formed in this part of the cavern. Some of the slender 

 branches were 6 or 7 inches long, and pointed from the roof and 

 sides in all directions. At one place it had grown horizontally from 

 the side, and the points of the branches were incorporated into a 

 mass of arragonite formed on a projecting corner ; indeed the inter- 

 lacing at this place resembled a tangled underwood. 



There was the least arragonite formed on the east side of the 

 cavern ; that little, however, was exceedingly beautiful. In two or 

 three small cavities in this side, the branches had grown in a slanting 

 or horizontal direction, and touched the opposite side, where each 

 one split into two or thi'ee flattened points, which in their direction 

 conformed and slightly adlieied to the opposing side. This pheno- 

 menon is represented in fig. 2. 



At one time stalactites of considerable length hung from the roof 

 of the cavern. From some unknown cause these had been subjected 



