SHELLS. 



ihis'iTseans made very beautiful, but they are by no means 

 to be regarded as inllruftors in natural hiftory. There are 

 feme artificers of this nation who have a way of covering 

 ftiells all over with a different tinge from that which nature 

 gives them ; and the curious are often deceived by thefe 

 tricks into the purchafing of them as new fpecies. 



There is another kind of work beitowed on certain fpecies 

 of fhells, particularly the nautilus ; this is the engraving on 

 it lines and circles, and figures of ftars, and other things : 

 this i»too obvious a work of art to fuffer any one to fuppofe 

 it natural. Bonani has figured feveral of thefe wrought 

 fhells at the end of his work ; but it is miferably throwing 

 away labour to do them : the (hells arc fpoiled as objefts of 

 natural hiftory by it, and the engraving is feldom worth any 

 thing. They are principally done in the Eaft Indies. 



Shells are fubjeft to feveral imperfeftians : feme of thefe 

 are natural, and others accidental ; the natural ones are the 

 eifeft of age, or ficknefs in the fifh. The greateft mifchief 

 happens to fhells by the fifh dying in them. The curious 

 in thefe things pretend to be always able to diftinguifh a 

 fhell taken up with the fifh alive, from one found on the 

 fhores : they call the firft a living, the fecond a dead fhell, 

 and fay that the colours are always much the faintelt in the 

 dead fhells. When the fhells have lain long dead on the 

 ftiores, they are fubjeft to many injuries, of which the being 

 eaten by fea-worms is not the leafl : age renders the finefl 

 ftells livid or dead in their colours. 



The finelt fhells are thofe which are fiflied up at fea, not 

 found on the fhores. The other natural defefts of fhells are 

 their having morbid cavities, or protuberances, in parts 

 where there fhould be none. When the fhell is valuable, 

 thefe faults may be hid, and much added to the beauty of 

 the fpecimen, without at all injuring it as an objeft of na- 

 tural hiftory, which fhould always be the great end of col- 

 lefting thefe things. The cavities may be filled up with 

 maftic, diffolved in fpirit of wine, or with ifinglafs : thefe 

 fubitances muft be either coloured to the tinge of the fliell, 

 or elfe a pencil dipped in water-colours muit finilh them up 

 to the refemblance of the reft, and then the whole fhell 

 being rubbed over with gura-vvater, or with the white of an 

 egg, fcarcely any eye can perceive the artifice : the fame fub- 

 itances may alfo be ufed to repair the battered edge of a fhell, 

 provided the pieces chipped off be not too large. And 

 when the excrefcences of a fliell are faulty, they are to be 

 taken down with a. fine file. If the lip of a fhell be fo bat- 

 tered, that it will not admit of repairing by any cement, the 

 whole muft be filed down to an evennefs, or ground on the 

 wheel. 



Shells, FoJJil. See Cokchology and Petrifactions. 



Shells are frequently found under ground, in places far 

 remote from the fea, in mines, and even on the tops of 

 mountains ; but how they fhould come thither is a thing 

 that naturalifts are greatly divided about. The moft ufual 

 and eafy opinion is, that thofe parts have been formerly fea, 

 or, at leafl, have been overflown thereby ; and many even 

 go back as far as the grand deluge for this. Others take 

 thefe to be the natural places of their birth or formation, 

 fome of them being found little other than crude clay, 

 others of the fame texture with the rock to which they 

 grow, though others feem of as abfolute a fhelly fubftance 

 as any in the fea. In effeft, they fay, thefe may be only 

 fo many different gradations of nature, which can as well 

 produce fhells in mines as in the fea, there being no want 

 of faline or earthy particles for the purpofe ; nor is there 

 any great difference between fome forts of fpars and fea- 

 ihells. 



Dr. Lifter judges, that the lh«lls found in ftone quarries 



were never any part of an animal, and gives this reafon for 

 it, that quarries of different ftone yield quite different fpecies 

 of fhells ; different not only from one another, but from 

 any thing in nature befides, which either fea or land does 

 yield. This opinion has been fince proved erroneous, and 

 all thefe bodies to have been really once parts of living ani- 

 mals. See Fossils, Adventitious, Marine Remains, and 

 Formed Stones. 



Of thefe fhells, fome are found remaining almoft entirely 

 in their native ftate, but others are varioufly altered, by 

 being impregnated with particles of ftone, and of other 

 foflils ; in the place of others there is found mere ftone or 

 fpar, or other native mineral body, expreffing all their 

 lineaments in the greateft nicety, as having been formed 

 wholly from them, the fhell having been firil depofited in 

 fome folid matrix, and thence diffolved by very flow de- 

 grees, and this matter left in its place, on the cavities of 

 ftone and other fohd fubftances, out of which (hells had 

 been diffolved and wafhed away, being afterwards filled up 

 lefs flowly with thefe different fubftances, whether fpar or 

 whatever elfe ; thefe fubftances, fo filling the cavities, can 

 neceflarily be of no other form than that of the ihell, to the 

 abfence of which the cavity was owing, though all the nicer 

 lineaments may not be fo exaftly expreffed. Bcfide thefe, 

 we have alfo in many places maffcs of ftone formed within 

 various fliells ; and thefe having been received into the ca- 

 vities of the fhells, while they were perfectly fluid, and 

 having therefore nicely filled all their cavities, muft retain 

 the perfect figures of the internal part of the fliell, when 

 the fhell itfelf fhould be worn away, or perifhed from their 

 outfide. The various fpecies we find of thefe are in many 

 genera as numerous as the known recent ones ; and as we 

 have in our own ifland not only the (hells of our own fhores, 

 but thofe of many other very diitant ones, fo we have alfo 

 many fpecies, and thofe in great numbers, which are in 

 their recent ftate, the inhabitants of other yet unknown or 

 unfearched feas and fhores. 



The cockles, mufcles, oyfters, and the other common 

 bivalves of our own feas, are very abundant ; but we have 

 alfo an amazing number of the nautilus kind, particularly 

 of the nautilus graecorum, which though a fhell not found 

 living in our own, or any neighbouring feas, yet is found 

 buried in all our clay-pits about London and elfewhere ; 

 and the moft frequent of all foflile fhells in fome of our 

 counties, are the conchx anomix, which yet we know not 

 of in any part of the world in their recent ftate. Of this 

 fort alfo are the cornua ammonis and the gryphitae, with 

 feveral of the echinitas and others. 



The exadt fimihtude of the known fhells, recent and foffile, 

 in their feveral kinds, will by no means fuffer us to believe, 

 that thefe, though not yet known to us in their living ftate, 

 are, as fome have idly thought, a fort of lufus naturae. 



It is certain, that of the many known fhores, very few, 

 not even thofe of our own ifland, have been yet carefully 

 fearched for the flacll-fifh that inhabit them ; and as we fee 

 in the nautilus grascorum an inftance of fhells being brought 

 from very diftant parts of the world to be buried there, we 

 cannot wonder, that yet unknown fhores, or the unknown 

 bottoms of deep feas, fhould have furnifhed us with many 

 unknown fheU-fifh, which may have been brought with the 

 reft ; whether that were at the time of the general deluge, 

 or the effeft of any other catailrophe of a hke kind, or 

 by whatever other means to be left in the yet uiihardened 

 matter of our ftony and clayey ftrata. Hill's Hift. of 

 Foft". p. 616. 



FolTiIe fhells are found to be of great ufe in manuring 

 land. S«e Manuring. 



4 They 



