Vol. 58. ] CRYSTALLINE LIMESTONES OF CEYLON. 403. 
diopside ; a variety common in the Hakgala district consists of 
diopside, blue apatite, and mica. The blue apatite ‘ from a locality 
near Newara Eliya’! (actually Lower Albion, near Hakgala, see 
map, Pl. XIV) occurs in a mass of this kind several yards in 
diameter, slightly quarried in the hope of obtaining mica of value. 
Carbonates are, as a rule, nearly or quite absent from these aggre- 
gates. The associations met with include:—Pure diopside (the 
commonest type); diopside, phlogopite, blue apatite (common) ; 
diopside, phlogopite, blue spinel (near Tataluoya) ; tremolite, calcite, 
blue apatite, colourless phlogopite (two-fifths of a mile south-south- 
west of Ulisna Muduna trigonometrical station, Pl. XIII); tremolite 
alone (36 miles north of Kandy); clinohumite (near Gettembe) ; 
olivine (Harakgama, Pl. XIV); olivine, green spinel, calcite, pale 
phlogopite (Mount Olive, Pl. XIV); olivine, pale phlogopite, pink 
spinel, tremolite, calcite, graphite, blue apatite, pyrite, rutile 
(disused middle quarry at Gettembe); phlogopite alone (several 
localities). 
The limestones vary much in coarseness of grain. The finer 
varieties are saccharoidal; the coarsest-grained consist of indi- 
viduals measuring over 4 inches along the rhombohedral edge. 
This exceptionally coarse variety forms a thin band of limestone, 
exposed by the roadside about a third of a mile east-south-east 
of Talatuoya Bridge. Speaking generally, the limestones are 
distinctly coarse-grained, and the individual accessory minerals are 
always clearly visible to the naked eye. 
The limestones vary as much in purity; almost pure varieties 
have a specific gravity of 2°76 to 2°78; in very impure varieties 
(rich in olivine) the specific gravity may reach 2:92, and that of the 
silicate-aggregates is, of course, still higher. 
Sometimes the carbonate-individuals are not uniform in size, but 
there are porphyritic crystals embedded in a finer matrix. In one 
case examined the larger crystals consisted of dolomite, the smaller 
of dolomite and calcite mixed, and intergrown. These porphyritic 
limestones occur at several points in the Hakgala district. Neither 
in them nor elsewhere are the carbonate-crystals idiomorphic. 
The proportion of calcite and dolomite present varies considerably. 
It is always posssible to separate the two carbonates by means of 
the Lemberg®* stain, which may be applied either toa thin section or 
to a smoothed surface of rock. The only other distinctions between 
the carbonates of which I have made use in microscopic work, are the 
difference of refractive index and the twinning, which is usually, 
but not quite invariably, characteristic of the calcite only. 
Microscopic examination of the limestones shows that they have 
not suffered from deforming earth-movements since the development 
of the accessory minerals that characterize them.’ In one case curved 
* A. H. Church, ‘ Nature’ vol. lxiii (1901) p. 464. 
* ‘Zur mikroskopischen Untersuchung von Calcit, Dolomit u. Predazzit’ 
Zeitschr. Deutsch. Geol. Gesellsch. vol. xl (1888) p. 357. 
* It will be gathered that I am inclined to regard all these accessory minerals 
as original, that is, as contemporaneous with the carbonate rock-constituents. 
