Coral in 
general. 
240 NATURAL HISTORY 
corals : thefe maffes are fomewhat gritty on the exterior, but within 
almoft as compact as ivory. Of the fame kind are fome with larger 
tubes, found, as well as I can recoiled, on the fea-fhore near Penros in 
Sithney, in the fame bay. I cannot help adding here the Porus 
cervinus Imperati u , commonly reckoned an Italian coral, but found 
in our feas. This rare coral, Plate xxiv. Fig. vii. was taken up 
by a filherman at the Pole-bank, which lies two leagues fouth-weft 
of Gilftone, Scilly ; at the fame place was found the thin cup-like 
Efchara , Fig. x. which is the millepora Retepora JLfchara marina 
of Ellis, Plate xxx. d , page 53. 
All thefe, as well as the corallines before-mentioned, and the foil'll 
corals alfo (fuch as the brain-ftone and the like, of which Cornwall 
yields none that have reached my notice) are radically compofed of 
the fame fubftance; all fhells alfo (as well of land-animals of the tefta- 
ceous kind, as of iiihes), the eggs of birds, and even the pearl itfelf are 
but finer pieces of workmanfhip of the fame materials, railing the fame 
effervefcence with aqua fortis, but of different colours, different de- 
grees of purity and confiftence, and different fhapes. It may not be 
amifs therefore to trace this fubmarine general compoft, as far as it 
is found in fea-produdions, through fome of its moft obvious me- 
tamorphofes. Coral is a calcareous fubftance, fparry (more or lefs) 
and argillaceous, partly extraded by the fea from the jlrata which 
it wafhes, and partly owing to the putrefadion and diffolution of 
the parts of dead animals, chiefly of the teftaceous kind. In its 
moft minute ftate, it nourifhes fea-plants and animals ; it furnifhes 
a glue and earth to the teftaceous fifties, enabling them to form their 
own fhells : as it floats in the waves in a lefs diluted and pulpy 
ftate, it is fometimes bom up by tempefts, and difperfed over the 
face of the ground, either by its lalt and limy particles, warming 
and fertilizing both corn and pafture w , or fixing and concreting the 
land of the fea-fhore into ftone *. When larger affociations are 
formed, they are precipitated by their own weight, and the impulle 
of the fea-water : what fubfides thus, if it meets nothing in its 
defcent, refts as a fediment in the more fheltered parts of the bot- 
tom of the fea ; if it fixes in its way down, it ferves as a balls for 
other nubecula of the fame fort to form themfelves upon, arrefting the 
little bead-like calcareous fubftances which come within its Iphere. 
Hence fome of the incruftations on ftones and fea-wracks ; for it is 
plain that coral, when unimpregnated with active fait, feed, or egg, 
muft fix like earth in a humble proftrate pofition, as an incruftation 
only, Fig. 11. Plate xxiv; if agitated by the waves, then it folds itfelf 
into a Lichen- like foliage, as Fig. in. ibidem ; if, whilft it fivims 
“ Ellis, page 72. w See page 84. * Page before, 95- 
at 
