I02 FENTTI ESKOI.A. M.-\. Kl. 



Garnet-bearing Labradorite-rock in Other Regions. 



It is, of course, oï grcal intcrcsl lo know, whether other occurrences 

 of plagioclase-rocks, or anorthosites, share this feature of containing garnet 

 of such eclogite-garnet character. Unfortunately I could not decide this with 

 certainty. From the anorthosites and labradoritc-rocks of Kiew and Wolynia 

 in Russia' and Monhegan Island in Maine^ no garnets have been mentioned. 

 In the large Morin anorthosite mass-^ in Canada garnet is very common, but 

 is often found near its contacts in varieties rich in iron ore. PVom its 

 occurrence: around iron ore grains where these are embedded in plagioclase 

 it seems to be the usual posterior corona-garnet and is probably almandite. 



Perhaps more similar to the Norwegian garnet-labradorite-rocks are 

 the anorthosites of the Adirondacks'* in which "deep pink garnets are well-nigh 

 universal, and often associated in the most intimate way with the pyroxene. 

 The relation makes one suspect that the garnet has resulted from preexi- 

 sting pyroxene. In anorthosites proper reaction rims — do not appear".^ 



At any rate, these phenomena are exceedingly rare, and positive 

 evidence of the existence of eclogite-like inclusions and eclogite-garnet has 

 not yet been obtained from any area of labradorite-rocks other than those 

 in the Bergen and Sogn regions in Norway. 



Eclogite near the Sørdal Mine, Ytre Holmedal, 

 Sogn og Fjordane Fylke. 



Among all the occurrences of eclogite in the coast range only those 

 at the Serdal mine occur in immediate connection with Silurian rocks, here 

 represented by mica-schists, quartzites and talc-schists, as described by 

 Tellef Dahll^. The eclogite outcrops on the north side of a narrow valley, 

 and on the other side, in contact with the schists, is found iron ore which 

 contains lenses and bands of the eclogite garnet. The ore is a spinel- 

 bearing magnetite-rock with 18.82 ^ TiO., and 51.33 ^ Fe. 



This iron-ore is regarded by Tellef Dahll as a contact-separation from 

 the eclogite, which he believes to be an igneous rock. 



The eclogite has been described microscopically by Mohl, Riess and 

 Kjerulf (see literature, p. 26 1. I have had thin sections made of specimens 

 of this occurrence from Ramsgronaave and Hordens. 



' W. Tarassenko, abstract in N. J. 1899, I, 459. 



2 E. C. E. Lord, A. G. XXVI, p. 340, 1900. 



3 F.D.Adams, N.J. Min. etc. B.-B. VIII, 1893, p. 447. 



4 J. F. Kemp, Bull. Geol. Soc. Am. 1894, V, p. 216. 



5 Through the kindness of Dr. N. L. Bowen and Prof. W.J.Miller 1 was later able to 

 determine the garnets in several specimens of anorthosite from th-e Adirondacks. They 

 all proved highly almanditic (60 mol. ^ aim). 



6 M. Irgens og Th. Hiortdahl, Om de geologiske Forhold paa Kyststrækningen af Nordre 

 Bergenhus Amt. Med. Tillæg 2: Jernforekomsten ved Sordal af Tellef Dahll. Universi- 

 tetsprogram for andet Halvaar 1864. 



