440 THE CANADIAN NATURALIST. [Vol. Vlii. 



stone. A vein at Krageroe exhibits still more distinctly a similar 

 sequence of crystallisation of the minerals in the hornblende 

 veins. The side portions consist of a mixture of finely granular 

 hornblende, with grains of apatite; from this rather sharply 

 defined zone the large crystals described above project into the 

 central vein-mass. We explain this arrangement in the following 

 way, viz., that the zone of the finely granular mixture crystallised 

 while the vein-mass was still in motion : on the cessation of its 

 upheaval, there first solidified, along with apatite, the above- 

 mentioned large crystals and the coarsely radiating hornblende 

 that occurs in their continuation, along with rutile, and, finally, 

 the rest of the coarsely radiating hornblende and the apatite 

 associated with it. 



The coarsely crystalline hornblende in the middle of this Kra- 

 geroe vein exhibits another phenomenon that seems irreconcilable 

 with a gradual deposition of the minerals from solution, viz., 

 large spheroidally arranged crystals of hornblende radiating from 

 a centre inside of the vein ; the formation of these may be readily 

 explained by the assumption that the crystallisation of the liquid 

 vein-mass took place not only on the walls of the country-rock, 

 but also about a centre inside of the magma. We recollect, 

 moreover, that in several of our deposits of apatite fragments of 

 rock occurred in the vein mass and surrounded by it. Joh. 

 Dahll states that at a considerable depth in Lykkens mine 

 at Krageroe rock fragments occurred in such quantity that a 

 genuine breccia was formed. But the most remarkable of these 

 observations is the discovery of small (about two inches long), 

 angular, sh;irply defined fragments of rock, which were enclosed 

 in the apatite of our Oedcgardskjern vein. These fragments 

 consist of granular quartz and some hornblende ; the country- 

 rock here is a gabbro somewhat similar to the " spotted " 

 gabbro of Oedegarden. Since neither the vein nor the surround- 

 ing rocks contain quartz and the fragments are in no respect 

 similar to the mineral aggregates that we have otherwise met 

 with in the veins, but are similar to several of our ordinary 

 quartzites, we can therefore scarcely doubt that they are also 

 true fragments of rock, which cauuot, on account of their charac- 

 ter, be derived from the country-rock. We are inclined to regard 

 them as fragments of rock that have been broken loose at a 

 considerable depth and brought to the surface by the liquid vein- 

 mass. 



