G. W. Tyrrell — Petrography of South Georgia. 483 



and Crusnes fields. Hence it is clear that German munitions of war 

 are being very largely manufactured from French, ore, thus 

 diminishing the potential mineral wealth of that country, in addition 

 to the actual damage inflicted by the said munitions during the War. 

 These are facts which will have to be taken into consideration at 

 the Peace Conference. 



II. — Additional jS^otes on the Petrography of SotFTn Georgia. 



By G. W. Tyrrell, A.E.C.Sc, F.G.S., F.E.S.E., Lecturer in Geology, 

 University of Glasgow. 



rMHE rocks which form the subject of this paper were collected by 

 1 the captain of a whaling vessel belonging to the fleet of 

 Messrs. Salvesen & Co., of Leith, stationed at Leith Harbour, South 

 Georgia. The collection reached me, for description, through the 

 kind ofiices of Mr. D. Ferguson, Mem. Inst. M.E., who recently 

 visited the island, and who has described its geological features.* 

 Two previous collections of rocks from South Georgia have been 

 described by me, one collected by Mr. Ferguson during his visit,'* 

 the other collected in the same way as the present set.' 



The collection consists of twenty-six specimens, nineteen of which 

 are from Larsen Harbour, at the extreme south-eastern end of the 

 island, in the midst of the " altvulcanischer " area found by Heim.* 

 Three specimens are from Gold Harbour, on that part of the coast 

 that trends nearly due north and south near the south-eastern end ; 

 and four specimens are from King Haakon Harbour, about the middle 

 of the long, icebound, southern coast. Most of the material is 

 igneous, or derived from igneous rocks by alteration ; the few 

 remaining specimens belong to the sedimentary series of which the 

 greater part of South Georgia is built. The rocks may be classified 

 as follows : — 



1. Igneoits Rocks and their Derivatives. 



(1) Spilite. 



(2) Soda-felsite (Quartz-felsite of previous paper). ^ 



(3) Greenstone (Albite-dolerite ?). 



(4) Epidosite and other Yein Rocks. 



2. Sedimentary Rocks. 



1. Igneous Rocks. 



(1) Spilite. — Several specimens belong to this type, all derived 

 from Larsen Harbour. They are compact, grey-green, non- 

 porphyritic rocks, carrying veins of quartz, chlorite, and epidote. 

 In some specimens small amygdales of dark-green chloiite or 

 yellowish-green epidote occur. 



^ " Geological Observations in South Georgia": Trans. Roy. Soc. Edin. , 

 vol. 1, pt. iv, pp. 797-814, pis. Ixxxi-xei, 1915. 



- " Petrography of South Georgia " : ibid., pp. 823-36, pi. xciv. 



" "Further Notes on the Petrography of South Georgia": Geol. Mag., 

 dee. VI, Vol. Ill, 1916, pp. 435-41. 



* "Geol. Beob. ii. S. Georgien " : Zeit. Ges. Erdk., 1912, pp. 451-6. 



^ Op. cit., p. 438. 



