62 
NATURAL HISTORY. (Minerals.) 
[north 
of Carlsbad in Bohemia, particularly the pisiform limestone, or 
pea-stone, as also the globular variety (considered by some as 
magnesian limestone) found in the bed of a small river near Tivoli, 
and known by the name of Confetti di Tivoli;— roestone ;—the tufaceous 
limestone, in porous, spongy, cellular, tubular, and other imitative forms, 
as incrustation on various objects, such as on the human skull here de¬ 
posited, which was found in the Tiber at Rome ; calcareous deposition 
formed in a square pipe in a coal mine in Somersetshire * ; casts made at 
the baths of San Felippe, where moulds of medals, gems, &c., are placed 
in suitable situations to receive the «pray impregnated with calcareous 
particles.— Chalk. —Anthraconite or madreporite. — Marie, &c. Among 
the varieties of shell limestone the most esteemed for ornamental 
purposes is the Carinthian iumachella, or fire marble. Polished speci¬ 
mens of such granular, compact, and fibrous varieties of calcite as are 
familiarly known by the appellation of marbles, and of those that bear 
the name of alabaster in common with the finer varieties of sulphate 
of lime. 
Case 47. In this Case, besides some specimens of carbonate of mag¬ 
nesia, or magnesite, from. Baudissero and from New Jersey, are placed 
those substances which, being chiefly composed of carbonate of lime 
and carbonate of magnesia, are called magnesian limestone, com¬ 
prising Werner’s rhomb-spar, dolomite, and brown spar. Among 
the varieties of the first of these sub-species are those called tha- 
randite, and some modifications of pearl spar; among those of dolo~ 
mite, a remarkable one is that from Pittsfield, Massachusetts, North 
America, which exhibits a considerable degree of flexibility : and an¬ 
other having the same property will be found among the singular va¬ 
rieties of magnesian limestone from the vicinity of Sunderland. 
Case 48 contains Werner’s brown-spar, some of the varieties of 
which are with difficulty distinguishable from rhomb-spar and from iron- 
spar; ^;everal interesting specimens for figure, colour, and lustre, chiefly 
from Schemnitz and Kreninitz in Hungary, are deposited in this case. 
— Carbonate of iron, or siderite and iron-spar, crystallized, fibrous, mas¬ 
sive, and botryoidal(5p^<^roszc?erz^eof Hausmann).— Carbonate of man¬ 
ganese, or manganese spar, crystallized and in globular and botryoidal 
shapes of various shades of rose colour, on sulphuret of manganese, &c. 
Case 49. One-half of this Glass Case is occupied by the several 
varieties of carbonate of zinc, or zink-spar (also called calamine in 
common with the silicate of zinc or smithsonite in Case 26)-.‘Crystallized, 
botryoidal, and in other forms, among which are the pseudomorphous 
crystals, derived from modifications of carbonate of lime (zinc-bloom). 
—With this is placed the aurichalcite of Bbtticher, one of the sub¬ 
stances to which the name of kupfer-schaum has been given; it is a 
carbonate of zinc and of copper, and nearly related to some chemically 
unexamined varieties of what has been called scaly green calamine of 
Siberia, &c. (in this table), and to which also the buratite of Delesse 
appears to belong.—The other half chiefly contains the carbonates 
of lead, or lead-spar (cerussite of Maid.), among which are the deli¬ 
cately acicular varieties from the Hartz, and from Cornwall, accom- 
* The slab of the table in the middle of the room is composed of a stalagmitic 
calcareous deposition, which was found investing the interior of a square wooden 
pipe in Blythe Lead Mine, Derbyshire: the legs of the table are of black marble, 
from Bakewell. This table w-as presented by his Grace the Duke of Rutland. 
