186 



DB. C. E. TILLEY ON THE PETROLOGY OF [vol. lxxix. 



Titanite is usually present in spindle-shaped grains, or is 

 xenoblastic. 



The chlorite is an accessory constituent, having the properties- 

 of the chlorite of the chlorite-epidote-schists. It is in intimate 

 association with the hornblende. The texture of the rock is 

 distinctly crystalloblastic. 



This rock was selected for analysis as typical of the second 

 group of the Green Schists. In the accompanying table are re- 

 corded analyses of both igneous and metamorphic rocks of com- 

 parable composition. It will be clear from this table that the 

 rock is essentially of basaltic composition, similar to the Tertiary 

 basalts of the Western Isles of Scotland, and among metamorphic 

 rocks we find its analogues in hornblende-schists from the Lizard 

 and Norway, and in a greenstone - schist from Rainy Lake 

 (Canada). 





VII. VIII. 



IX. X. 



XI. 



XII. 



SiOo 



49-32 48-25 

 1482 14-06 

 3-08 3-39 

 7-27 . 9-38 

 7-94 6-60 

 11-25 10-82 

 2-54 2-54 

 0'32 1 0-61 



46-61 47-11 



15-22 19-75 



3-49 : 2-30 



7-71 4-59 



8-66 7-73 



48-64 

 14-99 

 3-42 

 7-76 

 7-76 

 9-60 

 352 

 0-52 

 1-25 



o-io 



1-90 

 0-16 

 0-30 

 0-29 



46-28 



14-24 

 393 



11-62 

 7-40 



11-28 

 2-48 

 0-81 

 0-28 

 0-05 

 1-70 

 015 

 0-02 

 0-15 



AI0O3 



Fe.,0 3 



PeO 



MgO 



CaO 



10-08 

 2-43 



0-67 



11-67 

 2-80 

 0-80 

 1-72 

 0-07 

 0-67 



o-io 



0-08 

 0-02 



NaoO 



KoO 



HoO+ 



2 - 26 2-08 2-07 



H 2 0- 



0-13 0-56 

 1-55 i 2-47 

 n.d. 

 n.d. — 

 n.d. 



1-10 

 1-81 



o-io 



0-13 



TiO- 



P 2 3 



MnO 



Accessories 



Totals 

 Specific gravity 



100-4 : ' 100-76 1 100-08 



99-41 



100-21 



100-39 



17° 'l4° 



T o 3-010 T o 3-003 



1 n 

 _ ,20° 

 2-87 l-fo 3-060 



— 



— 



VII. Hornblende-epidote-albite-schist, Signal-Station, Prawle Point. 

 VIII. Tachylvte of basic andesite, Kildonan, Eigg. Min. Mag. vol. xix (1922)' 

 p. 288. 

 IX. Olivine-basalt, Drynocli (Skye). A. Harker, ' Tertiary Igneous Rocks of Skye* 

 Mem. Geol. Surv. 1904, p. 31. 

 X. Amphibolite-schist (metamorphosed lava), Naversnes, Finno (Stavanger). 

 V. M. Goldschmidt, Vidensk. Selsk. Skrifter, No. 10 (1920) p. 12. 

 XI. Hornblende-schist, the Lizard. E. G. Radley, in J. S. Flett & J. B. Hill, 



Mem. Geol. Surv. 1912, p. 48. 

 XJI. Greenstone-schist islet in Rocky Islet Bay. A. C. Lawson, Mem. Geol. Surv. 

 Canada, 1913, No. 40, p. 50. 



The norm of this rock is : — 



Per cent. Per cent. 



Orthoclase 1-7 Hypersthene 16*3 



Albite 21-5 Olivine 0-8 



Anorthite 28"1 Magnetite 4-4 



Diopside 22*4 Ihnenite 2-9 



