in the Ceylon Granulites. 365 



is not quite clear. The bands of intrusive pyroxenite following 

 the granulite foliation planes tend to pass into lenticles, as if by 

 a process of pinching, the lenticular forms being exactly followed 

 by the granulite foliation planes ; this fact, and the junction 

 phenomena, makes it seem likely that the granulites were not in 

 a completely consolidated state when the pyroxenic material was intro- 

 duced. Similar ' pinching' is shown in Fig. II, PI. XX, p. 366, at X. 



2. In the bed of the Talatu Oya at Uduwela, near Kandy, there 

 are several exposures of pyroxenic rock. Fig. II shows sills of 

 pyroxenite (nearly pinched out at X) combined with dykes along 

 joint planes. A section (1067) of the junction at X shows the 

 intrusive rock to consist internally of an aggregate of colourless 

 diopside with a peripheral hornblendic zone passing into the 

 granulite, in which plagioclase and diopside are the dominant 

 minerals, and pyrite is also common. A section (1069) of the 

 pyroxene further from the edge shows only colourless diopside 

 with a trace of plagioclase and green spinel. A junction section 

 (1068) at (Fig. II) showed orthoclase diopside rock (granulite) 

 passing into a diopside plagioclase rock (pyroxenite) with accessory 

 pyrite, sphene, and apatite. The (subordinate) plagioclase has an 

 ophitic habit, enclosing more than one individual of diopside, which 

 is also intergrown with it in radiating root-like fashion. In the 

 central part of the dyke mica becomes abundant, and is arranged .in 

 planes perpendicular to the edges of the dyke, as indicated in 

 Fig. IIa, pi. XX, p. 366. One other slide (1066) from the place 

 marked XX shows an aggregate of diopside and amphibole with 

 a little accessory pyrite. 



Some smaller dykes at Uduwela are very micaceous ; a section 

 (1149) of one about an inch wide shows granulite (quartz-orthoclase- 

 plagioclase rock with a little diopside) passing successively into 

 diopside rock with a little plagioclase, diopside rock, and diopside- 

 mica rock. The mica is in hand-specimens the most conspicuous 

 mineral, and is arranged in planes perpendicular to the edges of the 

 dykes. 



3. Fig. Ill shows a zoned pyroxenite dyke cutting the foliation of 

 the Charnockite Series, exposed in the bed of a stream entering the 

 Badulla Oya from its right bank, about 8^ miles from Badulla and 

 near Nanla. The outermost zone (about 3 inches wide) shows 

 under the microscope (1147) a compact intergrowth of colourless 

 diopside (partly also in granular forms) with subordinate plagioclase. 

 The diopside intergrown with plagioclase exhibits root-like forms, 

 and the intergrowth is on a very fine scale, so that the plagioclase 

 is not easily recognizable. The central one or two inches of the 

 dyke are clearly marked by the presence of dark hornblende, 

 which in the hand-specimen can be seen moulded on idiomorphic 

 grey-green diopside in ophitic wire. In the thin section (1148) the 

 hornblende appears pale bluish green, with pleochroism a pale 

 straw, b bluish-green with a brown tinge, and c bluish-green. 

 This is the usual amphibole characteristics of the rocks now 

 described. 



