208 MR. J. PARKINSON ON THE GEOLOGY [May I9OI, 



rock, with greasy lustre and some yariation in degree of coarseness. 

 Felspar is present in considerable quantity, and also conspicuous 

 elongated grains of quartz. 



A specimen, less finely grained than usual, has been sliced for 

 examination. The ferromagnesian silicates (both biotite and horn- 

 blende) are inconspicuous. The two constituents which build up 

 the greater part of the rock are quartz and orthoclase with micro- 

 perthitic structure. Some of the felspars measure "4 inch across. 

 The quartz is occasionally micropegmatitic, and accessory minerals 

 are plagioclase, zircon, pyrites, and (?) apatite. 



Cropping out by the side of the road to Hakgala, close to the 

 quarry just mentioned, is a garnet-bearing rock closely related to 

 the above, but more finely-grained and richer in the ferromagnesian 

 silicates (specific gravity =3-11). A little farther on, in a quarry on 

 the left bank of the stream, the rock of the Newara Eliya quarry 

 appears. The rock is traversed by coarser quartz -felspar veins, 

 essentially the same as the coarse patches from the Newara Eliya 

 quarry, and in these rather large flakes of mica are scattered. 

 Occasionally the mica-flakes have a distinct orientation. 



A small exposure above and to the right of the road consists of a 

 banded garnetiferous gneiss, containing some quantity of pink felspar 

 and a good deal of (juartz. A vein or band of pink felspar and 

 quartz, recalling the pinker parts of the gneiss (from which 

 indeed it cannot be separated), traverses the rock roughly parallel 

 to its foliation. It measures about 3 inches across, and contains 

 patches of mica, j^o hard-and-fast line, as of a contact, can be 

 drawn between the two. 



About 230 paces down the road we find the compact greenish rock 

 of the Newara Eliya quarry (specific gravity =2'66). Thin sections 

 prove that this type is identical with the pinkish banded gneiss, 

 in spite of the rather striking difference of colour : hence there can 

 be, I think, no doubt that they form one group. 



A well-banded rock crops out about | mile below the entrance 

 to Hakgala Gardens. The more felspathic part is compact, greenish- 

 yellow, of uniform texture, of specific gravity 2*59, and contains 

 a pyroxene and a few inconspicuous red garnets. The pyroxene is 

 monoclinic and pleochroic, but the pink colour which distinguishes 

 this mineral elsewhere is almost imperceptible. The rest of the 

 section consists of an aggregate of quartz, orthoclase (microperthite 

 and microcline absent) and plagioclase (extinction 7°), and a few 

 grains of zircon. 



' (c) Ohiya. — The rocks of the railway-cutting between Ohiya 

 and the ascent to Horton Plains are identical with those of 

 Newara Eliya and the road to Hakgala, so that a detailed description 

 is unnecessary. 



Taken as a group, these rocks are distinguished, with a few 

 exceptions, by a greenish colour accompanied by a greasy lustre, 

 and usually by the presence of garnets. These garnets are asso- 

 ciated with hornblende, a pleochroic pyroxene, magnetite, and 



