424 THE.CRYSTALLINE LIMESTONES OF CRYLON. [Aug. 1902, 
Prof. Jupp expressed his gratitude to the Author for bringing 
forward a description of a district so interesting to geologists. The 
rocks described were similar to those of Burma, except in the 
remarkable absence of certain minerals, such as corundum and its 
derivatives. He found great difficulty, as the Author did, in 
realizing that the charnockites could be intrusive in the limestones. 
In Burma and Ceylon alike, whatever might be the case in Southern 
India, the limestones were remarkably subordinate to the silicate- 
rocks, instead of the reverse being the case (as we should expect, if 
the latter were intrusive in the former). He agreed with the 
previous speaker as to the difficulty of imagining the limestones 
to have behaved as igneous rocks, and yet their relations with the 
igneous rocks were puzzling in the extreme. He referred to the 
occurrences of Glenelg and Tiree as affording fine illustrations of 
the part played in such a complex by calciphyres. 
Mr. Greenty remarked that in the Hebridian Gneisses of the 
North-west of Scotland there was also a great preponderance of 
igneous over what appeared to be sedimentary material. The 
Loch-Maree Group was now generally regarded as sedimentary, but 
it Was a comparatively narrow zone, while from Loch Maree to Cape 
Wrath all appeared to be igneous. Limestones were a conspicuous 
feature of the Loch-Maree Group, but they were accompanied 
by graphite-schists, mica-schists, and other probably sedimentary 
rocks. 
The Avurnor, in reply to Mr. Holland, said that no doubt in most 
cases crystalline limestones were a result of the recrystallization of 
calcareous rocks under pressure ; behaviour as a plastic medium did 
not involve a very high temperature, as had been proved by the 
work of Adams and Nicolson. But the limestones of Ceylon 
possessed a number of peculiar characters which, taken together, 
suggested to him that they had existed in ‘a state akin to 
fusion.” With regard to the interrupted sills, if this phenomenon 
was due to ‘pinching’ while both rocks were in a solid state (as 
Mr. Holland had suggested), why did the narrow lime-silicate 
contact-zones completely surround the lenticles, instead of occurring 
only on two sides of the granulite, as in the sill itself? Moreover, 
the accessory minerals in the limestones would show some trace of 
deformation if such powerful earth-movements had affected their 
matrix. 
In reply to Mr. Greenly, the Author said that rocks composed 
mainly of biotite and garnet, which could be regarded as of sedi- 
mentary origin, were scarce; no rocks with kyanite, andalusite, or 
sillimanite were known in situ. Even if such exist, and are the 
remains of sedimentary rocks, the igneous rocks must greatly exceed 
them inamount. No graphitic schists had been found. Finally, the 
Author said that he had no wish to lay great stress on his ‘ igneous” 
theory, and he regarded the descriptive portion of his paper as of 
much more importance than the theoretical. 
