Vol. 58. ] CRYSTALLINE LIMESTONES OF CEYLON. 42] 
about 12 miles east of Kandy. To reach the spot the Kandy- 
Badulla riverside road is taken as far as the Pallekelle ferry, which 
is crossed, and proceeding along the road to the Teldeniya rest-house, 
the village of Ambakotte is reached. Immediately after passing 
this village, a road must be followed which turns to the right across 
the ‘ Ambakotte’ and ‘ Ambakotte New’ Estates. The pits are on the 
farther side of the latter, some 2 miles distant from the main road. 
Several bands of limestone and granulite are passed on the way. 
Limestones are well exposed near a pond about halfway between 
the road and the pits. 
The pits show intimately interbanded acid granulite and impure 
limestone. The bands do not exceed a few feet in width, but are 
usually thinner. This is probably a case of ‘ lit-par-lit’ injection 
in the outer part of a band of limestone which is crossed before 
the pits are reached. The acid granulite is of the usual type, 
with much elongated quartz, and a tendency to graphic structure. 
The minerals are orthoclase-microperthite, orthoclase, quartz, and 
plagioclase. Large augen-orthoclases provide the moonstone, to 
obtain which the pits were dug. Individuals may reach a size of 
12°5 x 10 centimetres. 
The granulite-bands are separated from the lmestone by a 
contact-zone, first of compact granular diopside 2°5 to 5 centimetres 
wide next to the limestone, and secondly of diopside, serendibite, 
green spinel, sometimes scapolite and plagioclase, 1°25 to 2°5 centi- 
metres wide. Similar lime-silicate rock occurs inthin nodular bands 
which alternate with the granulite, corresponding to bands of lime- 
stone so thin as to have been completely altered to silicate-rock. This 
type of contact-action (formation of diopside, etc.) recalls the cases 
described on pp. 409, 410. Alternate bands of acid granulite and 
limestone were noted also in another moonstone-pit near Talatuoya. 
The serendibite has a dark bluish-green colour in the rock, 
and with the spinel gives it asimilarhue. It rarely occurs in easily 
recognizable crystals, but is usually much mixed and intergrown 
with the diopside. In thin sections, it is rendered very conspicuous 
by its remarkable pleochroism from very pale yellowish-green! to 
deep indigo-blue, and by the multiple twinning which is as charac- 
teristic as in a triclinic felspar. The crystals are somewhat 
flattened and elongated, and the twin-plane is parallel to the 
elongation. Crystal-faces parallel to the elongation are fairly well 
seen, terminal faces are rarer. The crystals have sometimes an 
ophitic habit, so that several portions not in contact extinguish 
simultaneously. 
Other characters may be summarized as follows :—Optically 
biaxial, probably triclinic, perhaps monoclinic. Cleavage none ; 
hardness=ahbout 7; specific gravity =3°42. Refractive index nearly 
equal to that of diopside, double refraction weak. 
* In thin slices the spinel and serendibite are indistinguishable for some 
positions of the lower nicol. 
O23. Go sNo. 231. 26 
