124 
LONG 
GALLERY. 
Nat. Hist. 
near Tivoli, and known by the name of Confetti di 
Tivoli; the tufaceous limestone , in porous, spongy, 
cellular, tubular and other imitative forms, as incrus¬ 
tation on various objects, such as on the human skull 
here deposited, which was found in the Tiber at Rome ; 
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 par¬ 
ticles.— Chalk.—Anthraconite or madreporite.— Marie , 
& c. 
Case 49. In this Case, besides some specimens of 
magnesite , or carbonate of magnesia, 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 , 
or dolomite, comprizing Werner’s rhomb-spar, dolo¬ 
mite and brown spar. Among the varieties of the first 
of these subspecies are those called miemite, tharandite , 
and some modifications of pearl spar; among those of 
dolomite , a remarkable one is that from Pittsfield, Mas¬ 
sachusetts, North America, which exhibits a consider¬ 
able degree of flexibility, and another having the same 
property will be found among the singular varieties of 
magnesian limestone from Sunderland; among the 
varieties of Werner’s hr own spar or pearl spar , which 
in some cases is with difficulty distinguishable from 
rhomb spar, several interesting specimens for figure, 
colour and lustre, are deposited in this Case, and con¬ 
tinued in 
Case 50, which is partly occupied by those fibrous 
varieties of brown spar, several of which were formerly 
referred to common fibrous limestone.— Carbonate of 
iron , or sparry iron ore , crystallized, fibrous, massive, 
and botryoidal ( splicerosiderite of Hausmann).— Car¬ 
bonate of manganese , in globular and botryoidal shapes 
of various shades of rose colour, or sulphuret of manga¬ 
nese, &c.—The remainder of this Table Case is occu¬ 
pied by the several varieties of carbonate of zinc, crys¬ 
tallized, botryoidal, and in other forms, among which 
are 
