Reports and Proceedings— Geological Society of London. 45 
a pyroxene-bearing microgranite is found also; while the hornblende- 
granite is cut by rhombic-pyroxene bearing veins and also contains 
angular masses of rock resembling the veins. 
The following grouping of the Pulau Ubin rocks (with which is 
included a rock found in the granite of Changi) is adopted. 
Normal hornblende-granite with a little monoclinic pyroxene. 
TOT 
Pyroxene-microgranite with dark masses resembling ITI (i). 
III. 
(i) Porphyry, with peculiar spongy masses of hornblende. 
(ii) Masses of a rock at Changi having the mineral constitution of an amphibole- 
vogesite. 
Vi 
(i) Ves of quartz-norite in the normal granite. 
(ii) Veins and masses of enstatite-spessartite in the normal granite. 
(ui) Masses of quartz-biotite-gabbro in the normal granite. 
Pulau Nanas consists of dacite-tuffs and dacite which are referred 
to the Pahang Volcanic Series, of Carboniferous or Permo-Carboniferous 
age. The tuffs and lavas have been altered by the adjacent granite of 
Pulau Ubin, and contain much secondary biotite and hornblende. 
They also contain some fragments that appeared to be altered chert, 
but their most remarkable feature is the presence of fragments of 
altered granite. 
The author discusses the mutual relations of the different rocks, 
and arrives at the following conclusions :— 
(1) The normal granite of Pulau Ubin is hornblende-granite, the 
age of which is certainly post-Triassic and pre-Eocene, perhaps post- 
Inferior Oolite and pre-Cretaceous. 
(2) Veins of quartz-norite and masses of quartz-biotite-gabbro, and 
veins and masses of a fine-grained rock which may be described as 
enstatite-spessartite, are found in the normal granite of Pulau Ubin. 
These point to an early differentiation of a granite and a gabbroid 
magma, perhaps in pre-Cretaceous times, and they are referable to 
rocks in Borneo and Amboyna. 
(3) A pyroxene microgranite and porphyry on Pulau Ubin, and 
a rock at Changi, having the mineral constitution of an amphibole- 
vogesite, are described. Their relations to the other rocks are not clear. 
(4) The dacite-tuffs of Pulau Nanas contain fragments of granite 
which must be of pre-Carboniferous age, and are referable to the 
granite of Amboyna. 
(5) The fragments of granite, and perhaps certain pebbles of schorl- 
rock, are the only evidence found as yet in the Malay Peninsula of 
pre-Carboniferous rocks. 
4. ‘The Tourmaline-Corundum Rocks of Kinta (Federated Malay 
States).” By John Brooke Scrivenor, M.A., F.G.S. 
Overlying the limestone on the west side of the Kinta Valley is 
a thin cap of schists, with which are found certain rocks the two 
chief constituents of which are tourmaline and corundum. They are 
often carbonaceous; and, in the many variations found, white mica, 
brown mica, pleonaste, rutile, and metallic sulphides occur. 
The tourmaline-corundum rocks contain certain structures which 
