168 PYROXENE GRANULITES 



typical pyroxene granulite with granulitic fabric and small, even grainsize ; it contains 

 pyroxene and felspar in about equal amounts. The felspar is in small rounded grains, 

 almost undecomposed and with albite twinning. The larger grains of felspar have, 

 however, undergone a certain amount of sericitisation. The pyroxene is the same as 

 has already been described for these rocks. The other half of the section, on the other 

 hand, approaches very close to a pvroxenite ; it is composed almost completely of 

 rounded, rather small grains of pyroxene. The grains are medium in size and are the 

 same as the pyroxene in the first-mentioned half of the rock. 



P. 216. Pyroxene Granulite, Erratic (Cape Royds). 



Hand-specimen missing. 



Under the microscope the fabric is granulitic and the grainsize uneven and fine 

 to medium. 



The minerals are : pyroxene, felspar, quartz, sphene, and magnetite. Pyroxene 

 is in fairly large grains and is, as usual, colourless ; it forms nearly half the rock. Felspar 

 is in large allotriomorphic grains, twinned sometimes after the albite law but often 

 untwinned. It is somewhat decomposed and is a basic labradorite, extinctions in 

 symmetrical sections going as high as 37°. Quartz is not at all abundant and has 

 shadowy extinction. Sphene is in numerous small crystals, and magnetite is present. 



In conclusion, the writer desires to express his thanks to Professor David and Sir. R. E. 

 Priestley for the opportunity to do this work and for their kindness and assistance, 

 and also to Mr. Gr. J. Burrows for his invaluable help with the analyses. 



LITERATURE 



For full references up to 1896 see Judd in Phil. Trans., 1896. 



1900. Coomara-Swamy, A. K. " On Ceylon Rocks and Graphite," Q.J.G.S., lvi, p. 592. 

 Adams, F. D. Annual Report Geol. Survey, Canada, viii. 



1904. Kastner, Max. " Zur Genesis des sachsischen Granulitgebirges," Centralbl. 



Min. Stuttgart, 1904, pp. 196-206. 

 1903. Coomara-Swamy, A. K. Geol. Mag., 1903, pp. 348-350. 



Prior, G. T. " British East Africa," Min. Mag., 1903, pp. 229-231. 



1901-2. Lowe, H. J. " The Sequence of the Lizard Rocks," Trans. R. Geol. Soc, 



Cornwall, 1901 (pp. 438-466) and 1902 (pp. 507-534). 



1906. Evans, J. W. " The Rocks of the Cataracts of the Madeira River," Q.J.G.S., 



1906 (pp. 88-124). 



1907. Credner, H. " Die Genesis des sachsischen Granulitgebirges," Centralbl. 



Min., 1907 (pp. 513-525). 



1907. Peach, B. N. " Home, J., etc.," Mem. Geol. Surv. Gt. Brit., 1907 (xviii and 



668). 



1905. Coomara-Swamy, A. K. " The Rocks and Minerals of Ceylon," Spolia Zeylan, 3, 1905 



(pp. 50-66). 



1908. Bergt, W. " Neue Vorkommnisse von Pyroxengranulit und iiber dessen 



Allgemeine Verbreitung," Berlin, Monatsber D. geol. Ges., 

 1909 (pp. 231-234). 



EXPLANATION OF THE PLATE 



Figure 1. Pyroxene Granulite, Erratic, No. 960. 



Figure 2. Pyroxene Granulite, Erratic, No. 1537. 



Figure 3. Pyroxene Granulite, Erratic, No. 584. 



Figure 4. Pyroxene Granulite, Erratic, P. 355. 



Figure 5. Pyroxene Granulite, Erratic, No. 1515. 



