[ 6 o ] 
either fharp or rounded. They are, not without 
Reafon, fuppofed to be a Part of fome Sea Produc¬ 
tion petrified. They are very frequently met with 
in many Parts of England: at Cleydon in Oxfordshire 
they are found rather larger than common, but of 
a fofter Subftance; for, on being left a fmall Space 
of Time in a ftrong Acid, they may eafily be fepa- 
rated at the Joints in fmall Plates. 
: The Irochites and Entrochi are nearly of the 
Subftance and Size of the JJleri<e, but not fulcated ; 
they are compofed of a Number of round radiated 
Joints, refembling in fome meafure fo many fmall 
Wheels. They are generally found in Strata of 
Clay here and abroad. 
The Ajlrcites when put into Vinegar have a Mo¬ 
tion. They are often picked up at Cutworth in 
Northamptcnfhire , at Shugbury in Warwickshire , and 
about Belvoir Caftle in Lincolnfhire ; a fmall Kind 
are found near Lajfington in Glocejlerjhire. 
Ichtyolithi , petrified Parts of Fifh. Among the 
Specimens are Slaces of various Colours, with na¬ 
tural and diftind Marks in them reprefenting the 
Skeleton of fome Fifh, or the Parts thereof. 
In the Mines in Derbyshire are found the petrified 
Bones of many Kinds of Fifh; fome of them bear 
an exad Refemblance to the Vertebrae of a Floun¬ 
der. 
Under this Title we take notice of the Glojfopetra , 
formerly fo called, becaufe it was imagined they 
were petrified Tongues; but they are in truth the 
Teeth of Sharks and other Fifh, fcmetimes adhering 
ftrongly and partly buried in a ftony Subftance, at 
others loofe; our more modem Naturalifts have 
very properly called them Icbtyvdontes. 
Here are alfo depofited the Bufonites, Toadftones. 
There is nothing in Nature refembles them fo much 
