348 JOURNAL OF THE PLYMOUTH INSTITUTION. 
certainly, and perhaps greatly, exceeding four feet; but it was 
occasionally much less, and in some instances there was none. In 
short, its depth was greatest, and its upper surface attained the 
highest level, at the external entrances, whence it sloped down- 
wards and became less deep in every direction. It ‘‘ thinned out”’ 
before reaching the southern end of the Eastern Division—though 
small ‘‘pockets” of it were met with further south—and its 
thickness was very limited in the Western Division, especially in 
its southern portions. In all cases, however, it extended beyond 
the foot of the declivity which its upper surface formed. 
6th. Wherever the bottom of the Cave-earth was reached, there 
was found beneath it a floor of Stalagmite having a crystalline 
texture, identical with that of the isolated masses incorporated in 
the Cave-earth as already mentioned. This, designated the Crystal- 
line Stalagmite, was usually of greater thickness than the upper 
or Granular floor vertically above it, and in some instances but 
little short of 12 feet. Where there was no Cave-earth, the 
Granular Stalagmite lay immediately on the Crystalline. 
7th. Below the whole, occurred, so far as is at present known, 
the lowest and oldest of the deposits which the Cavern contained. 
It was composed of sub-angular and rounded pieces of dark-red 
grit, with a comparatively small number of quartz pebbles, 
embedded in a sandy paste of the same colour. Small angular 
fragments of limestone, and thin investing films of stalagmite, 
both prevalent in the Cave-earth as already stated, were extremely 
rare; large blocks of limestone were occasionally met with, and 
the deposit, to which the name of Breccia was given, was of a 
depth exceeding that to which the exploration has yet been carried. 
The masses of Crystalline Stalagmite and the fragments and 
lumps of dark-red grit found embedded in the Cave-earth were 
undoubtedly portions, not im situ, of the older deposit—the 
Crystalline Stalagmite floor and the Breccia, Nos. 6 and 7, just 
described,—and show that these accumulations had been partially 
broken up by some natural agency before and during the introduc- 
tion of the Cave-earth, and that they were formerly of greater 
volume than at present. In all cases the Breccia attained a higher 
and higher level with increased distance from the known external 
entrances to the Cavern; thus suggesting that it was introduced 
through undiscovered openings in what is now termed the “inner 
extremity’ of the Cavern. In short, the Cave-earth and Breccia 
