J, V. Elsden — Origin of Pegmatite Veins. 311 



be discovered. As previously stated, well-defined rifts exist in the 

 granite. These rifts run not only parallel to the joint planes, but 

 also along well-defined though faint foliation planes in the granite, 

 usually cutting transversely across the direction of the folded 

 pegmatites. I do not, therefore, think it possible that there can be 

 any mistake in the conclusion that the folding of the pegmatites 

 occurred before the main mass crystallised. 



In the Morrum district, a few miles to the south-west, similar 

 phenomena can be observed, but here the pegmatites are sometimes 

 disposed in very regular planes, about six feet apart, parallel to the 

 well-defined foliation in the parent rock. Whether these are un- 

 contorted, or whether they owe their appearance to being cut 

 transversely, viz., parallel to the axes of the folds, is not certain. 

 At Matvik, on the coast, a few miles east of Carlshamn, I noticed 

 similar veins of pegmatite, parallel to highly inclined foliation planes, 

 dividing so as to enclose a ' horse ' of the country rock, but without 

 any disturbance of the regular foliation of the parent mass. Very 

 striking relations between the folded veins and the foliation planes 

 of the granite were seen at Kiilleron, to the west of Carlshamn. 

 Here the appearance was as i-epresented in Fig. 3. It is difficult to 



J'iG. 3. — Contorted pegmatite in gneiss, Kiilleron, near Carlshamn, Sweden. The 

 double arrow indicates direction of foliation of the gneiss. Scale, about Jjj. 



escape from the conclusion that the pressure which induced the 

 foliation also operated in the production of the contortions in the 

 pegmatites while the mass was still in a viscous condition. Nor can 

 any theory of subsequent vein filling adequately account for the 

 phenomena. It must be mentioned, also, that the pegmatite veins 

 are not themselves foliated, which is probably to be attributed to the 

 fact that the solidification of the veins took place subsequently, under 

 difi'erent conditions from those prevailing during the crystallisation 

 of the main rock, as I shall endeavour to explain later. This result 

 might readily be produced if we assume that the foliation was 

 produced by a gentle shearing force at a time when the minerals of 

 early consolidation were already formed, while the substance of the 

 veins still remained in a state of viscous fluidity. This would also 

 account for phenomena noticed in the neighbouring island of Giinon, 

 where the foliation planes appear to be slightly deflected by contact 

 with the margins of the pegmatites. Nearer Carlshamn I saw many 



