Petrifactions. MINERALOGY. Petrifactions. 
lhell. Several fpecies of this are known foflils, fome of 
which approach very nearly to thofe which are recent, 
and one in particular appears to differ very little from 
the M. modiolus, which is found in various parts of 
Germany, fixed and marmoreous. The other principal 
ones are: 
a. Mytilus crifti-galli; found in Malta, Normandy, 
Swiflerland, Germany. It is f'ometimes very large, and 
generally marmoreous. 
y. M. frons ; found in Chriftianftadt in Sweden, in Bel¬ 
gium, Normandy, and Malta; in marble, fand, or flint. 
M. margaritiferus; this is found near Ariflorf in 
Swiflerland ; admitting a beautiful polifh, and exhibiting 
the moil fplendid iridelcent colours, according to its po¬ 
rtion in the light. 
9 . M. edulis ; found in Piedmont, and very many parts 
of Germany; generally fixed and calcareous j f'ometimes 
ferruginous, or in fandftone. 
19. Helmintholithus pinnites; the pinna. Found in a 
foflil ftate in Piedmont, near Ariflorf in Swiflerland, in 
Franconia, and near Drefden in Saxony. 
20. Helmintholithus nautilites; the nautilus. Speci¬ 
mens of this, in the foflil ftate, are very frequent. They 
have been found in feveral parts of our own illand : fome 
fine fpecimens have been met with at Lime in Dorfetfliire, 
in different parts of Wiltfliire, and at Whitby in York- 
fhire. The fineft fpecimens are thought to be found in 
the neighbourhood of Bath, and in the ifle of Sheppey in 
Kent. In digging for the Highgate-archway, a number 
of very beautiful fpecimens were difcovered, fome exceed¬ 
ingly large, and ftill retaining a refplendent pearly fhell, 
highly decorated with pyrites. 
The fhell with the outer whorl much larger than the 
others is common in Northamptonfliire, Kent, Sheppey, 
and other parts of England; alfo in many countries on 
the continent. It is generally marmoreous; f'ometimes 
pyritaceous, or filiceous. 
That with the circumference rounded and knotty, and 
the grooves tranfverfe and flexuous, is met with in almofl 
every part of the globe, in marble, limeflone, clay, marl, 
fwineftone, hornllone, agate, flint, &c. from the lize of a 
fixpence to more than two feet in diameter. The cham¬ 
bers are often filled with cryflals of various kinds. 
The N. belemnita is found abundantly in many parts 
of England, particularly in Glouceflerfhire and Oxford- 
fhire, and in molt mountainous parts of Europe. They 
are more or lefs opaque or tranlparent, ilraight or a little 
bowed, cylindrical, conic, more or lels clavate, fufiform, 
a little compreffed, pointed or rather obtufe, with a groove 
or two towards the tip; internally hollow or filled up, 
from a quarter of an inch to eight inches long; the colour 
is whitifh, amber, grey, brownifh, or blackifh. They are 
often incloled in, or adhere to, other Hones; are com- 
pol’ed of feveral crufts encircling each other; and are 
molt frequent in chalk, gravel, or clay. When burnt, or 
fcraped with a knife, they give out an odour like ral'ped 
horn. Common people have a notion that they are to 
be found after a thunder-ftorm. 
21. Helmintholithus coni; the conus. Met with in 
Piedmont, Swiflerland, and TranfyIvania ; and commonly 
has a marble nucleus. 
22. Helmintholithus porcellanites; the Cypraea, or 
cowrie. Found marmoreous in Piedmont and Aultria. 
23. Helmintholithus bullites; the bulla. Found near 
Northberg in Germany. 
24. Helmintholithus cylindrites; the voluta. This, 
which has generally a marble nucleus, is found in Swif- 
ferland, Piedmont, near Verona, in Aultria, Saxony, and 
Germany. 
25. Helmintholithus buccini; the Buccinum, or whelk. 
Of the feveral fpecies of this, the angular, or B. bezoar, 
is found on the hills near Hampton, in this country; 
alfo in Swiflerland, the Netherlands, and Germany. 
26. Helmintholithus Itrombi. The Stroinbus cliiragra 
Vql.XV. No. 1 063. 
529 
is found near Oedenburg in Hungary. S. lucifer with a 
long fpire, near the warm bath in Wirtemberg. 
27. Helmintholithus muricis. Several fpecies of the 
Murex, or whelk, are found foflil. The M. granulatus is 
met with in Italy and Auflria ; it is marmoreous, or filled 
with fandftone. 
28. Trochilites; the Trochus, or top-flone. We have 
fpecimens of each of the three divifions. 
a. Conic. Found near Bath ; and in Denmark, Swe¬ 
den, Norway, Saxony, Germany, &c. generally in lime or 
fandftone. A fpecimen of this diviiion is the Trochus 
zizyphinus, near Pfullingham in Wirtemberg. 
/ 3 . Convex. Found in Italy; mollly marmoreous, rare¬ 
ly filiceous. Example, the Trochus perl'peitivus, difco¬ 
vered in Franconia. 
y. Turretted. The Trochus telefcopium ; found near 
Brendola, in the Venetian territories. 
29. Helmintholithus turbinites ; the Turbo. Found in 
various parts of Europe. 
a.. Solid. Met wfith in Piedmont, Weltphalia, and many 
parts of Germany; generally in marble, quartz, or fand¬ 
ftone. Of this diviiion the Turbo littoreus is found in 
Swiflerland and many parts of Germany ; f'ometimes filled 
with fpar, or covered with arborefeent figures. T. coch- 
lus is found near Diefenhof in Swiflerland. T. rugofus, 
in Belgium and Franconia. T. marmoratus, farmaticus, 
and argyroflomus, in Wirtemburg. 
( 3 . Cancellate. The T. fealaris is found in Swiflerland 
on Mount Hexenburg, rare. T. ftriatulus, near Scliem- 
nitz in Hungary, marmoreous. 
y. With an elongated fpire. Six fpecies are met with 
in England, France, Swiflerland, Italy, Silefia, Bohemia, 
Saxony, Germany, &c. aggregate and fixed, generally 
in marble, flint, chalcedon, or fandftone, and fometimes 
filled with fpar. 
30. Helmintholithus helicis; the Helix, or fnail-fhell. 
as. Flattened; found in various parts of England, Bel¬ 
gium, Swiflerland, Hungary, Germany, &c. detached or 
fixed, folitary or gregarious, or mixed in marble, flint, 
or fandftone. ( 3 . Bounded; near Verona in the Vene¬ 
tian territories, in Piedmont, Swiflerland, and Germany. 
y. Ovate with a point; in England, France, Germany, 
Swiflerland, Aultria, Bohemia, Saxony, &c. in marble or 
fandftone. 
31. Helmintholithus neritites; the Nerita. Found in 
Piedmont, Swiflerland, Carinthia, Auflria, Germany, &c. 
generally in limeflone. 
32. Helmintholithus auricularis; the Haliotis, or fea- 
ear. Found in Belgium and Saxony. 
33. Helmintholithus patellarise; the Patella, or limpet. 
Found in various parts of England, Swiflerland, and 
Italy. The Patella laccharina is common in various parts 
of Sweden. 
34. Helmintholithus dentalis ; the Dentalium, or tooth- 
fhell. Four fpecies occur in various parts of Italy, Swif- 
ferland, Germany, Bohemia, Silefia, and Saxony; in mar¬ 
ble, jatper, or chalcedony. The Dentalium fexangulare 
is found near Loretto in Italy. 
35. Helmintholithus tubulites. The Serpula is to be 
met with in many of the countries of Europe. The flexu¬ 
ous or contorted, called vermicularis, is found in Malta, 
Italy, Swiflerland, Germany, Franconia, and Belgium ; 
in marble or fandftone, generally leafed on other petri¬ 
fied fhells. 
36. Helmintholithus teredinis; the Teredo. Found in 
Sheppey illand, and Piedmont, in lubterraneous wood. 
37. Helmintholithus fabellse; the Sabella. Found every¬ 
where among impreflions. 
38. Helmintholithus tubiporites ; the Tubipore. Met 
with in Sweden, Belgium, Franconia, and-Silefia. 
a. T. muiica ; found in England, Belgium, Germany, 
Gothland, in marble, quartz, or landltone. 
8 . T. catenularia ; in Gothland and Brandenburg ; 
marmoreous. 
6 T y. T, 
