from Guadaloiipe, 115 
When more closely examined, it is found to consist of yel- 
lowish grains, intermixed with others of a more or less deep 
flesh red colour. These grains, though minute, are in some 
parts of the mass perfectly defined, and in close contact with 
each other, although no cement is perceptible ; in other parts 
they are, as it were, confluent, forming a more or less porous 
mass; in others again they form a compact mass, in which 
the former distinct concretions, especially the red ones, are 
only indicated by a difference of colour. 
The red grains that enter the composition of the rock, ap- 
peared at first view to be particles of red coral (isis nobilis), 
which has hitherto been found only in the Mediterranean ; 
but on closer examination, their structure proved them to be 
the detritus of a millepora, and indeed one fragment of a 
larger size than the rest renders it probable that it is mille- 
pora miniacea of Pallas. The last mentioned fragment was 
coalesced with a piece of very compact white madrepore, and 
intimately connected with the surrounding mass. Shells also 
are found in this rock : the one most distinct is a helix, ap- 
proaching in form and size to helix acuta of Martini, (Con- 
chiol. Vol. IX. Pi. XXX. fig. 224.), but differing in the 
form of the whorls which are less convex and distinct, and 
have three bands on the body volution, instead of one. An- 
other shell, of which a few only were discovered in the mass, 
appears to be turbo pica of Linnaeus in a worn state: the 
brown spots are still distinctly seen on its surface. Dr. Leach 
intends to dedicate a plate of one of the next numbers of his 
“ Zoological Miscellany'* to the illustration of these and some 
other shells related to them. 
Besides these bodies, I found, near the surface of the block, 
O 2 
