26 Foreign Notices in Mineralogy, &c. 
and that they are in part, if not wholly, of volcanic origin.* 
One of the specimens, which is now in my cabinet, is very 
much in favour of this opinion. It is a fragment of a Tra 
rock, composed of augite and felspar, and cannot readily be 
distinguished from portions of the Trap rocks of Iceland. 
is specimen is about six inches in length, and has an ir- 
regular prismatic form. Nearly the whole of one side of it 
is covered with balexdony, and small rock erystals. This 
is evidently part of alarge drusy cavity. ‘The calcedony. has 
a slightly bluish colour, and is rather more than half an inch 
in thickness ; and the transparent crystals rest upon it. 
A second specimen is composed of jasper and calcedony. 
The jasper is red, (about the colour of arterial blood,) with 
bands of light yellow, and brown ; the surface is irregular, 
and is covered on one side with calcedony of a most deli- 
cate flesh colour, in small mamillary concretions, studded 
with innumerable minute brilliant crystalline points. 
The most singular specimen is a portion of a stalnctte, 
which has been broken transversely. Its length is t 
inches and a half, its diameter rather more than two. The 
exterior layer, which is about a quarter of an inch thick, is 
composed of crystallized transparent quartz, within which is 
a layer of milk. white calcedony of about the same thickness, 
and the centre of the specimen is filled by calcareous spar 
of a yellowish brown colour, and opaque. The calcareous 
spar is so hard near its junction with the calcedony, that it 
yields with difficulty to the knife. It however effervesces 
with an acid. The central portion is considerably softer. 
Among these specimens are many globular, and ovoidal 
inasses of caleedony, of various shades of white, grey, blue, 
and red. Their size varies from that of a hen’s egg to 
diameter of eight or ten — beans are Siohons and are 
inverse, cuboide, and metastatigue of E fiuy. The exterior 
of these ‘sender ie 3 irregular ‘having that in dented.surface 50 
* Mr. J. Miens, in the Edin. Philo. Jonr No.6, has given a ve inberasting 
t of the discovery of New South Shetland, se fro m the ay ra 
im m from the mate of one of the vessels which Has 
i mre to consid or tie const as ¢ sa danimaieener acter soe cho 
Soe 
