C ^80 ) 
the Radii and SVn^ on them that the commo n Shells 
of thofe forts of Fiflies have. 
All thefe Shell-fifti have their Shells on, fome of 
which Shells are exceeding thin, to what other fome 
are. Sometimes the Shells of fome of them are in their 
Petrifaftion fo throughly united unto and incorpora*" 
ted with the Stone^that they are fcarce vifible. Others 
in the fame Quarry have a thick white Shell on them 
petrify 'd, but not incorporated and turned into the 
fubftance of the Bed in which they lye. As you get 
that Fifli out,all the Shell flicks fo faft to the Rock* that 
moft commonly it is left behind, butfometimes the Shell 
cleaves in two, on half of the Shell on both fides of the 
Fifti fticks thereto, and the other half to both fides of 
the Bedjbut others come out by lying in theAirinfrofty 
nights, with the whole natural Shell on them, and the 
Radii or Stri£ very exaft. Other Fifh there are here 
that have a black fmooth Shell on them, with feveral 
Stri£ but no RacIH^ very like, if not the fame with the 
Concha. Nigra Rondeletii , figured in Gefmr de Pifcik 
p. 237. 
I have alfo feen and found in this Quarry fome 
Shell-fifh half open, juft as they will be in the bottom 
of a Pond when the Water has left them, and yet fil- 
led with the matter of the Bed in which they lye, and 
petrify'd with it. 
Others being in heaps together, I have found fome 
of them broken, others bruis'd, and the' edges of one 
Fifti thruft into the fides of another, fome with the 
one Shell thruft half way over the other, &c. and 
fo petrify *d in the bed together. 
Others in the fame Bed have been (o clofe, that the 
matter of the Bed f which I take to have been a fine 
blue Clay in the Antidlluvian World or intheN"^^^- 
chia?i DelugeJ could not infinuate irfelf into them. 
Hiefe that are thus found , are fome of them totally 
empty, 
