74 natural history. (Minerals.) [north 
joints, colour, &c.; likewise the various secondary obtuse and acute rhom- 
bohedrons; among the former of which the mostcommon,butnotthe least 
striking, is the inverse variety of Haiiy, so called from its being as it 
were an inversion of the primitive rhombohedron of calcareous spar; 
and the same with a considerable admixture of quartz, commonly called 
crystallized sandstone of Fontainbleau, &c.; also many interesting and 
beautiful specimens, from the Hartz, Derbyshire, Sec., of prismatic and 
pyramidal modifi cations of the same substance. 
Case 45. Besides additional chiefly prismatic modifications of ervs- 
tallized calcite, this Table Case contains several belonging to the sta- 
laclic and fibrous varieties of that substance, the most characteristic 
of which latter are those from Cumberland and Sweden, with pearlv 
lustre (which has obtained for the former the appellation of satin-spar), 
and that in coloured layers from Africa. 
Cases 45 A. and 45 B. are set apart for polished specimens 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 ala- 
baster in common with the finer varieties of sulphate of lime. Among 
the varieties of shell limestone in Table Case A., the most 
esteemed for ornamental purposes is the Carinthian iumachelia, or fire 
marble. 
Case 46 contains the remaining varieties of calcite, among which 
may be particularized the well-known depositions from the hot springs 
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 spray impregnated with calcareous 
part ides .—Ch a Jk . —A n th race n i te or madrepori te. — Marle . & c. 
Case 47. In this Case, besides some specimens of carbonate o f 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, or dolomite, 
comprising Werner’s rhomb-spar, dolomite and brown spar. Among 
the varieties of the first of these sub-species are those called miemite, tha- 
randiie, and some modifications of pearl spar ; among those of dolo¬ 
mite, a remarkable one is that from Pittsfie4d, 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 aud from iron- 
spar; several interesting specimens for figure, colour and lustre, chiefly 
* 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 Bakewel!. This table was presented by his Grace the Duke of Rutland. 
