742 PROF. T. G. BONNET ON SPECIMENS COLLECTED BY [Nov. 1 896, 



(ii) Boulders from tundra in the neighbourhood op 

 Sviatoi Nos, Kola Peninsula. 



(29.) A fine-grained reddish granite, rather rich in felspar and 

 poor in mica (biotite and a little muscovite). Examination of the 

 powder shows that some of the felspar is ferrite-stained, that micro- 

 cline is present, and that the iron oxide probably is haematite. 



(19, at Sviatoi jNTos.) A moderately coarse, rather felspathic, 

 reddish- coloured gneissoid granite ; the biotite (not very abundant) 

 exhibits a slightly linear arrangement. A good deal of muscovite 

 is seen on close examination with a lens ; this also is found in the 

 powder, together with biotite and a very light brown mica, as well 

 as plagioclastic felspar and microcline. The outer surface of the 

 fragment has assumed in weathering a peculiar, rather lumpy, 

 slightly glazed aspect. Possibly it may be part of a vein. 



(8.) A dullish red (slightly mottled) very fine-grained felspathic 

 sandstone, with a few specks of mica, bearing some resemblance to 

 Torridon Sandstone, but with smaller grains than is usual in that 

 rock. Examination of the powder shows the quartz-fragments to 

 be angular in form and somewhat ferrite-stained, with plagioclase 

 and microcline among the felspar, also a tiny chip of garnet. 



(24.) A whole stone, labelled 'miniature boulder,' about 3" X 

 1*75" x 2*25", rudely oblong, slightly tapering at one end. This 

 appears to be a granitoid or slightly gneissoid rock. 



(26.) An ovoid pebble, rather blunted at one end, of moderately 

 coarse, pale-red gneissoid rock. 



(16.) A fine-grained dioritic rock with a very slight approach 

 to a foliated structure — felspar light-coloured, hornblende dark. 

 Examination of a slice shows the following minerals : — (a) Green 

 hornblende, strongly dichroic, with occasional inclusions (see 22, 

 p. 743) in irregularly-shaped grains ; (b) biotite in fairly idiomorphic 

 flakes, often in close association with the hornblende, as if formed 

 at its expense ; (c) felspar — in quantity about one-half of the rock 

 — in irregularly- shaped grains, being often moulded on the mica ; 

 occasionally slightly decomposed, much of it plagioclase, with both 

 albite- and pericline-types of twinning. Sometimes a grain, which 

 with ordinary light appears single, is found on applying the nicols 

 to be composite. A few grains of quartz, granules of iron oxide, 

 and several microliths of apatite also occur. The structure is 

 peculiar: it may be the result of dynamic action, but there is 

 nothing to prove this ; possibly it is due to a partial fusion anterior 

 to final consolidation, by which biotite has been produced at the 

 expense of original hornblendic and of felspathic constituents. 



(iii) Bocks in place, Fiord of Ueanskoe River, 

 Kola Peninsula. 



(20 — At edge of water close to camp, June 24th.) A rather coarse 

 gneissoid rock, with some approach to a banded order in its con- 

 stituents — like Archaean specimens from Greenland and Norway. 



