HOLWELL CAVERN. 15 
the main one, running nearly at right angles to it. At 
the extreme western end of this cavern is a small pool of 
water, supplied by a little spring which percolates the 
rock and passes off through the bottom of the pool. The 
entrance into the cave has its roof and sides covered with 
stalactitic carbonate of lime, and you descend several 
steps, which have been hewn in the rock to allow a better 
ingress ; and the main fissure has likewise been widened 
artificially for the same purpose. The roof and sides of 
the western end are more or less covered with snow-white 
erystals of arragonite, in great variety—massive with 
fibrous erystals diverging from a centre—coralliform, com- 
posed of aggregations of diverging cerystals, (flos ferri), 
mostly translucent, rarely transparent—the colour varying 
from a snowy white to pale red, but mostly the former. 
These crystals readily scratch common carbonate of lime, 
and even glass, but with some difficulty. Water is con- 
stantly dropping from the projections of the roof at the 
western end, and the arragonite would be slowly in- 
creasing were it not forthe depredations committed on it 
for some time past by collectors of specimens, who, not 
contented with fracturing it in all directions, have partially 
blackened the roof by the smoke of candles. Very large 
stalactites and stalagmites also have been removed, so that 
the cavern presents a very different appearance from what 
it originally did when first discovered. It has been stated 
both by myself and others, that all the common carbonate 
of lime found in this cavern has been formed solely upon 
limestone, and all the arragonite upon clay-slate—Since 
this statement has been made I have closely examined the 
matrix upon which these cerystallizations are deposited, and 
though I still find a very large proportion of arragonite 
upon the clay-slate, yet I find a considerable quantity of 
