OCCURRENCE OF TINGUAITE AT KOSCIUSKO, N.S.W. 353 



conglomerate of considerable extent at Nightingale Island. The 

 cement of this conglomerate is formed of phonolitic material. 

 Nepheline is stated to occur in grains and crystals besides brown 

 microlites of augite and sanidine etc. 



In Brazil, Prof. O. A. Derby, 1 has described a nepheline-bearing 

 rock from Serra de Tingua. This, however, is perhaps more 

 referable to the elseolite-syenite-porphyries, leucite-elseolite-syenite- 

 porphyries or tinguaites than to the phonolites. Besides elseolite 

 it contains abundant pseudomorphs in analcime after leucite. It 

 was originally considered to be of Palaeozoic Age, but Hussak 2 has 

 shown that it intrudes Post-Carboniferous, perhaps Triassic, 

 sandstones. 



Kerguelen. — Phonolite has been described 3 at the above island 

 at Greenland Harbour. It is stated to be a greenish- white rock 

 forming cylindrical and columnar masses which rise above the 

 general level of the surrounding sheets of augitic basalt. Much 

 soda and sulphuric acid are present. 4 From the fact that angular 

 enclosures of the phonolite are met with in the basalt, (whereas 

 no basalt enclosures have been observed in the phonolite), and 

 from the fact that the basalts which are typically porphyritic 

 become less coarsely crystalline as they approach the dome-shaped 

 masses of phonolite, it is argued that the Kerguelen phonolites 

 are probably somewhat older than the basalts. Professor Roth 3 

 and Renard 5 have also described phonolite from Kerguelen. 



Mr. Evelyn G. Hogg, m.a., 6 has also described phonolites from 

 Kerguelen, and the adjacent Howe Island. At the latter locality 

 the minerals present in the phonolite are sanidine, augite, horn- 

 blende and nepheline. An analysis of this rock for comparison 



1 O. A. Derby, Q.J.G.S., xliii., 1887, 457 j xlvii., 1891, 251. 



2 Hussak, N. Jahrb. f. Min., 1890, i., 166 ; 1892, n., 146. 



3 Report Scientific Results, Voyage H.M.S. Challenger, Narrative, Vol. 

 I., First Part, pp. 348 - 351, and p. 374. 2 Op. cit., p. 350. 



4 Roth, (Prof. J.) Ueber die Gesteine von Kergueland, Monatsber. d. 

 K. preuss. Akad. d. Wiss. Berlin, 1875, pp. 723-735. 



5 Bull. Musee roy. de Beige iv., 1886, 223, and Rep. on petrology of 

 Oceanic Islands, 1889, 133. 



6 Hogg, (E. G.) Proc. Roy. Soc. Victoria, Feb. 1899, Vol. xi., (New 

 Series) Pt. 2, pp. 209-213. 



W— Dec. 4, 1901. 



