96 ME. A. K. COOMARASWAMY ON [Feb. I903, 



The presence of some of these inclusions is evidently the result of 

 crush-brecciation (fig. 5, p. 99) ; others seem to be more or less 

 modified portions of intruded rock, and recall similar inclusions in 

 the crystalline limestones of Ceylon. 



There occur also small pegmatite-patches in the eastern part of 

 the exposures of marble in the field south-east of Balephetrish Hill. 



(2) Mineral- aggregates. — Small and large augen of pure 

 white sahlite (the largest measuring 6 feet by 4) occur in the white 

 marble of the field south-east of Balephetrish Hill ; the foliation of 

 the marble sweeps around these on a large scale, just as on a smaller 

 scale it bends round the little augen consisting of single grains of 

 diopside or forsterite. 



Near the spot marked ' Natural Arch ' numerous dark mineral- 

 aggregates occur in the pink marble, varying in size from a 

 few inches to a foot or two in diameter, and of quite irregular 

 lumpy shape. These weather out on the surface, being often 

 attached by quite a narrow neck. They consist of dark-green 

 coccolite, scapolite, sphene, and blue apatite, with also calcite and 

 colourless or brown mica (PI. VII, fig. 3). The first four minerals 

 are especially characteristic ; the rock strongly recalls certain augite- 

 scapolite-spheue rocks from Ceylon. 1 The grains of apatite are 

 rather conspicuous, owing to their bright sky-blue colour ; this 

 occurrence of blue apatite again reminds one of Ceylon. 



III. Contact-Phenomena. 



Contact-phenomena are not especially well displayed, partly 

 owing to the earth -movements which have affected the rocks since 

 their formation, partly owing to the fact that contact-sections are 

 rather infrequently exposed. 



A contact of limestone with gneiss of acid type is seen at the 

 southern edge of the quarry at Balephetrish. The gneiss is composed 

 of quartz and felspar, exhibiting strain-shadows and partial granu- 

 litization ; a few rather large grains of zircon occur in addition. 

 The marble is one of the finest-grained types, with appearances of 

 ' streaming,' and with numerous grains of coccolite and also decom- 

 posed scapolite (?) and sphene. A dark zone, about half an inch 

 wide, separates typical marble from typical gneiss. In this zone, 

 on the side next the gneiss, the minerals hornblende and felspar 

 (triclinic), with a little accessory golden-brown mica, compose 

 the rock, while greenish pyroxene is rare. On the side next the 

 marble the zone contains pale-green monoclinic pyroxene (that is, 

 coccolite), scapolite with rather abundant sphene, and accessory iron- 

 ores. The change from hornblende-felspar-rock (modified gneiss) 

 to pyroxene-scapolite-rock (altered limestone) takes place rather 

 abruptly near the middle of the half-inch dark zone ; but the 



1 A. K. Cooimiraswamy, Quart Journ. Geol. Soc. vol. lviii (1902) pp. 407 & 

 680. 



