9 6 NATURAL HISTORY 
quantity fufficient to conned the fand together, but not enough to 
concrete into a firm hard body. Dr. Woodward’s Cat. vol. II. p. 3, 
fays the inhabitants call it a kerned ftone ; that is, a coagulated 
ftone, but juft congealed ; and indeed it is no more than the blown 
fand incrufted into ftone in fo many thin feparate layers, one over 
another, as the fand was thrown in, mixed with the lparry fpray, 
at feveral fucceflive times, by the Northerly winds. Let no one 
wonder that the fpray of the fea fhall produce fuch an effecft ; 
for that fpar is fufpended in all water is likely ; but, in particular 
waters, is evident from incruftations formed in the bottom of culi- 
nary vefiels, and in water-pipes, from petrified mofs, and many 
other phoenomena ; and that fpar is alfo to be found in fea- water, 
muft certainly follow, from the fea being open to, and ready 
to receive, all that fprings will convey into it. All coralloeid 
bodies and (hells are formed of fpar, modified and mixed fo as to 
comply with the occafions of marine plants and animals Laftly, 
(par is wafhed out of the cliffs and rocks expofed to the power of 
the fea ; nay, great degrees of heat will raife it in vapour, and 
what rifes fo into the atmofphere, is doubtlefs again condenfed and 
precipitated by wind, cold, and rain h . In feveral parts of Corn- 
wall we have a lapis arenaceus or free-ftone, confiding of fand and 
quartz. Near the borough of Michell there is a pretty ftone, not 
long fince difcovered, of a cinereous ground, fpeckled with white 
gravel : it works very fmooth, and keeps a neat edge. In Gwenap 
there is a whiter ftone, and in Stithien one of the fame kind. 
Polrudon ftone (commonly called Pentowan) is likewife of the 
arenaceous kind. This ftone lies in a lode about fifteen feet wide, 
not interfered by horizontal and perpendicular fiflures, as in firata 
of free-ftone, but (helving, and in irregular mafles, aud of three 
different colours; the firft and fineft of a milk-white ground, 
thinly befprinkled with purple (pecks about the twenty-fourth part 
of an inch in diameter ; the fecond of a cinereous ground, with 
more, larger, but fainter purple fpecks ; the third of a yellow 
ochreous ground, fpeckled, but the purple lefs diftinff, with fome 
micaceous talc thinly interfperfed. Dr. Woodward’s Cat. vol. II. page 
4, had two fpecimens (b 2, b 3, ib.) from this quarry; one of an iron- 
colour, and indeed an irony-water, I obferved here to dilcolour 
(omewhat of the fuperficies of the (tones ; but in the heart, I found 
them always of one of the three before-mentioned colours. Dr. 
Woodward, ibid, calls this a free-ftone, and not improperly, if he 
meant only a lapis arenaceus ; but it is greatly different, both as to 
1 See page before, 84. 
h See Woodward’s Cat. vol. I. pa. 116 — 1x3, 
&c. “ About CappeHham the corals difperfed 
about the Ihores uniting with the fand, make a 
folid ftone.” Linnaeus Amsen. Academ. page 
463- 
ground 
