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APPENDIX. 
associated with beds of a calcareous breccia, cemented by magnesian 
limestone, and with beds of compact dolomite. 
There are no primitive rocks, and one specimen only which 
seems referrible to a granular quartz rock, more ancient than the 
new red sand stone. . 
A short descriptive catalogue of the specimens which have been 
brought home, with the assistance of the map in which all the 
names alluded to are inserted, will give the most ready information 
they are calculated to afford. 
The specimens are as follow : 
BASALT. 
No. 1, Basalt, nearly black, much impregnated throughout vdth 
carbonate of hme, and interspersed with small circular cells, that 
are partly or whoUy filled with common or with magnesian car- 
bonate of lime. The decomposition of this rock forms small spherical 
fragments of considerable hardness, the surface of which, by long 
exposure, has acquired a kind of poHsh or glossy aspect, and is 
irregularly pitted or indented all over with small cavities of various 
depths, from the destruction of the calcarous matter that originally 
filled them. 
A similar appearance of glossy polish is found on all the calca- 
reous specimens from this country, which appear to have been long 
exposed to the action of the atmosphere. In some of these the 
surface is entirely smooth and even ; in others, it is furrowed over 
with minute grooves and channels, intersecting each other with 
irregular curvatures, and resembling the appearance produced on 
the surface of compact hmestone that has been submitted to the 
action of acids, or corroded by small marine worms. 
It is not easy to determine the cause of this irregular destruction 
of the surface of hmestone, whose substance appears to be entirely 
uniform : it is probably the same that gives it the glossy pohsh ; 
but it seems doubtful, whether the agent producing it be the con- 
