Dr. Davy on the Geology and Mineralogy of Ceylon . 325 
must be variable in different instances, the harder kinds abounding 
most in carbonat of magnesia, and the softer in carbonat of lime. 
The only metal that I have hitherto detected in dolomite is iron, 
in the form of iron pyrites. 
The only minerals that I have discovered disseminated through it 
are the following: mica; apatite; a bright yellow mineral, which I am 
disposed to consider a variety of cinnamon stone, as it resembles cinna- 
mon stone in all its essential properties; white clay, apparently derived 
from the decomposition of felspar; graphite, and ceylanite. Mica is 
pretty common in dolomite ; generally of a straw colour, semitrans- 
parent, and in six-sided prisms. Apatite is rather less common ; it is 
either blue or green, and not distinctly crystallized. The mineral 
which I conceive to be a new variety of cinnamon stone, I have found 
in the neighbourhood of Kandy, disseminated in a large vein of do- 
lomite. Clay in dolomite is of rare occurrence. Graphite is often 
to be seen scattered through it in very minute scales. Ceylanite is 
more abundant in dolomite rock than any of the preceding minerals, 
and more generally disseminated through it. It occurs crystallized 
and amorphous, of various colours, bright, azure blue resembling 
the blue sapphire, violet, pink red, grey and white : its crystals are 
generally small and very small. I have found the fine sapphire blue 
variety only at Nalandi ; the other varieties occur in the neigh- 
bourhood of Kandy, and in a vein of dolomite not far from Ratna- 
poma in Saffragam. 
Connected with this rock, from which they are derived, I may 
mention three other minerals, calc-sinter, calc-tuff, and agaric-mineraL 
I have met with calc-sinter superimposed on dolomite at and beyond 
Naland. Calc-tuff is of common occurrence at a place called Puljsan 
Cadarette, and between this place and Trincomalie, in the channels 
