On the Occurrence of Corundum at Pont-Paul. 153 



account of the relations between the various granulitic rocks of 

 Ceylon. A series of more or less isolated sections were studied, 

 the rocks in each considered under separate heads, and conclusions 

 put forward relative to the whole. Two sectious are described to 

 the west, and one to the north, of Kandy, in which the rocks are of 

 a well-marked type. As a rule they are strongly, often coarsely, 

 banded : and the relation of the light and dark bands is such as to 

 lead the author to conclude that this structure arose ' through the 

 streaking together of the component parts of a magma which had 

 undergone differentiation.' The darker parts are characterized by 

 the presence of green hornblende in varying quantity, associated 

 with brown mica. Locally garnets are abundant, and pyroxene is 

 found in some slides. A fourth section, south of Matale, is of 

 importance, since it is believed that here a granulitic rock resembling 

 some described under the section which follows (Section V) is in- 

 trusive in a crystalline limestone. Modifications in the intruder 

 are described, which are supposed to have arisen through the local 

 incorporation of some of the older rock. Under Section V rocks 

 from Newara Eliya, Ohiya, and Bandarawella are grouped together. 

 These are often banded and vary considerably in coarseness, but are 

 distinguished, with few exceptions, by a greenish colour accom- 

 panied by a greasy lustre, and usually by the presence of garnet. 

 Hornblende, magnetite, and biotite are associated with this mineral, 

 and a pleochroic augite is not uncommon. The structure of all the 

 rocks described is granulitic ; that is, characterized by the irregularity 

 in the outlines of the grains which build up the rock, and by the 

 inclusion of one mineral by another. Porphyritic felspars are 

 recorded from several localities. 



The author concludes that the rocks of Section V are nearly related 

 to those described in the earlier part of the paper, and points out 

 the close resemblance of the whole to the Charnockite Series of 

 Southern India. 



2. ' Note on the Occurrence of Corundum as a Contact-Mineral at 

 Pont-Paul, near Morlaix (Finistere).' By A. K. Coomara-Swamy, 

 Esq., B.Sc, F.L.S., F.G.S. 



The intrusive granite of Pont Paul, near Morlaix, contains highly 

 altered fragments of sedimeutary rock. The minerals found in 

 them are biotite, muscovite, corundum (first recorded by Prof. Barrois 

 in 1887), plagioclase, andalusite, pyrite, magnetite, silliinanite, green 

 spinel, and zircon. The corundum forms sharply idiomorphic 

 tabular hexagonal crystals, striated and slightly stepped on the 

 basal plane, and blue in colour. Iron-oxide is a constant inclusion. 

 The inclusions have probably been to some extent injected with 

 felspathic material. The original sediment was probably poor in 

 silica and rich in alumina, and there has been sufficient molecular 

 freedom for the formation of well-shaped crystals of corundum, 

 comparatively free from inclusions. Sillimanite and zircon are 

 the only other minerals which exhibit crystalline form. 



