Vol. 56.] CEYLON KOCKS AND GKAPHITE. 595 



apatite, and zircon. The structure is granulitic. The garnets are 

 transparent and fresh. They show no trace of crystalline form, 

 but have a much corroded appearance ; in many cases the grains are 

 ■deeply hollowed out so as to be crescent-shaped, in others two or 

 three small grains near together appear to be the remnants of a larger 

 grain (see fig. 1, p. 594). The garnets are more often surrounded by 

 the microperthite than in contact with the abundant quartz. With 

 the corroded garnets and the microperthite is associated the brown 

 mica, which lies in the bays and hollows that appear to have been 

 eaten out of the garnets (PI. XXXIII, fig. 2). 



Type 3. Dondra Head (the southernmost point of Ceylon). — 

 Much crystalline rock in large boulder-masses is found on the shore. 

 In one specimen the minerals are orthoclase-microperthite, quartz, 

 plagioclase, garnet, hypersthene, hornblende, magnetite, apatite, 

 and zircon. The dark minerals are arranged somewhat in parallel 

 layers, and the quartz-grains are elongated in the same direction. 

 A precisely similar rock is found on the little island near the shore, 

 south of the rest-house at Ma tar a. 



Galle. — A very similar rock occurs in the quarry behind Galle 

 town, associated with some decayed and schistose rocks among 

 which a dark biotite-schist is found. 



Colombo. — Irregular exposures of dark rock overlain by laterite 

 are found near the site of the new graving-dock. The minerals 

 .are quartz (elongated grains), hypersthene, garnet, magnetite, and 

 spinel. The magnetite is fairly abundant, and usually contains 

 irregular patches and strips of resinous-looking, dark green, isotropic 

 spinel. Occasionally very small portions of this green mineral seem 

 to react on polarized light : this phenomenon may be due to local 

 •strain, or to the presence of chlorite. 



Kandy. — There is an extensive exposure of very various gneissic 

 rocks in the Mahaweli Gorge at Hakinda, near Kandy. A single 

 specimen (on which a species of Podostemon was growing) is a fine- 

 grained grey pyroxene-granulite composed of quartz, plagioclase, 

 augite, and some graphite. A distinct parallel arrangement is 

 noticeable, especially marked by the graphite and pyroxene : the 

 .appearance is suggestive of flow-structure. 



NeweraEliya. — A greenish rock collected between Newera 

 Eliya and the Eambodde Pass is a garnet-free pyroxene-granulite. 

 The minerals are plagioclase (20° 23°, probably labradorite), quartz 

 (elongated), pyroxene, apatite, ilmenite, apatite, and greenish 

 decomposition-products. 



Other pyroxene-granulites are described by Melzi [29] from 

 Pidurutalagalla, and Diersche [30] from the quarry between Newera 

 Eliya and Hakgala. They are also recorded by Dr. Diersche from 

 Raged ara, Adam's Peak, and the Dimbula Estate, and by Melzi 

 from Bandarawela (garnetiferous pyroxenite). 



