78 
natural history. (Minerals.) 
[north 
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 spray impregnated with calcareous 
particles.— Chalk.—Anthraconite or madreporite.—Marie , &c. 
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 miemite, 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; several interesting specimens for figure, colour and lustre, chiefly 
from Schemnitz and Kremnitz in Hungary, are deposited in this case. 
-— Carbonate of iron, or siderite and iron-spar, crystallized, fibrous, mas¬ 
sive, and botryoidal {splicer o siderite of 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 Botticher, 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 Haid.,) among which are the delicately acicular varieties 
from the Kartz, and from Cornwall, accompanied and partly coloured 
by green carbonate of copper; the crystallized varieties from Siberia, 
Mies in Bohemia, &c.;—the pulverulent variety, &c.— Carbonate of 
bismuth, from the principality of Reuss.—To which are added some 
specimens of the rare carbonates of cerium, as coating on cerite, from 
Bastnas ;—of yttria on orthite, from Ytterby, Sweden, &c. 
* 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 was presented by his Grace the Duke of Rutland. 
