No. 7.] APATITE IN NORWAY. 427 



rock passes into a finely granular, almost compact, greenish rock. 

 The portion of country-rock enclosed by the net-work of veins 

 is partly a peculiar variety of the "spotted gabbro," which on 

 account of its appearance has received from the miners there the 

 appropriate name of "sandrock." Its peculiarity is that the 

 labradorite crumbles between the fingers into very small 

 grains like the grains of a friable sandstone ; and it often con- 

 tains small scales of a brown mica, instead of hornblende or 

 diallage. Its sp. gr. is 2.79= Farther eastward this sandrock 

 borders the mic - mass. 



Several mica veins, the largest being quite 25 feet thick, were 

 Gpme upon farther eastward by digging through the clay that 

 overlies the foot of the ridge. Still farther eastward a long pro- 

 specting trench cut through the soil in a N. W. and S. E. direction 

 exposed not fewer than twelve veins. They all dipped slightly 

 towards the ridge and were tolerably parallel to one another, 

 the largest being six feet thick. Only one of these veins seemed 

 to contain much apatite ; the others consisted of phlogopite en- 

 closing some lumps of apatite and hydrous enstatite. 



The second important vein to be described is very rich in 

 apatite. It dips slightly (about 30°) towards S. E.; and its 

 outcrop was traced by exposures for about 160 feet. The banded 

 arrangement of the minerals formiug the vein, which is usual 

 in the richer veins of this deposit, is very marked here ; the 

 sides being lined with a slight belt of brown phlogopite, while 

 the centre is almost exclusively filled with apatite. In the vein 

 the thickness of pure apatite was 7 — 8 feet ; this being the 

 greatest yet observed at Oedegarden. The cross-stringers here 

 exhibit the only instance known to us iu this deposit where the 

 apatite comes directly in contact with the country rock. 



The third vein is a six-foot mass- of mica-bearing apatite, 

 which is forked and shattered towards the east, and has been 

 traced for about 70 feet. 



No. 4 resembles No. 2. 



No. 5. One larger and several smaller veins, striking in dif- 

 ferent directions, are here close together. As usual, the centres 

 of the veins consist of apatite, separated from the country rock 

 by brown phlogopite. They are enclosed on both sides by a zone 

 of the above-mentioned " sandrock," whose limits are somewhat 

 sharply defined against the ordinary " spotted gabbro." 



In this neighbourhood there occurs a small 8-inch vein, which 

 Vol. VIII. bb No. 7. 



