No. 7. J APATITE IN NORWAY. 441 



A phenomenon which also seems best explained by the assump- 

 tion of the eruptive nature of the veins, is seen in the twisted and 

 bent crystals of various minerals that frequently occur in several 

 deposits. In the Oedegarden veins bent crystals of enstatite 

 often occurred. Still more frequently are the large plates of 

 mica in veins of apatite crumpled and twisted. At Roenholt 

 bent and twisted crystals of rutile occurred embedded in the 

 other minerals of the vein. A pair of bent and twisted crystals 

 of apatite an inch long, which — to judge by other crystals found 

 at the same place — must have been surrounded by a homogeneous 

 mass of quartz, seemed very remarkable. The crystals of apatite 

 when first formed, while the mass of quartz was still plastic, 

 may have obtained their present contorted shape from the pres- 

 sure caused by the motion of the quartz. 



We must also mention the broken crystals of enstatite at Oede- 

 garden that are cemented by apatite, and the fragments of 

 crystals of hornblende that occur in magnetic pyrites on the 

 saalbaender of many veins. Both occurrences make it probable 

 that the entire vein mass did not simultaneously solidify. This 

 is also indicated by the banded arrangement of the veins. It is 

 probable that the apatite and magnetic pyrites were still a plastic 

 mass when the minerals of the saalbaender had already crystal- 

 lised out. And when these latter, in consequence of the motion 

 of the vein mass, were broken they were cemented by the apatite 

 or magnetic pyrites. 



We may here recall to mind the crystals embedded in mag- 

 netic pyrites, that were rounded and even fused on the edges 

 and corners. 



As already mentioned, where the apatite-bearing veins occur 

 in strata, they are perfectly independent of their strike and dip ; 

 showing in this respect the usual behaviour of eruptive veins. 



We must mention still another point wherein these veins differ 

 from ordinary metallic veins, viz., in the entire lack of empty 

 spaces filled by crystals dividing them into two symmetrical 

 halves. Even ordinary geodes are met with only as rare phe. 

 nomena in the apatite-bearing veins. 



Apatite has been long known as a mineral crystallisable out of 

 a hot liquid mass. Forchhammer obtained small crystals out of 

 a fused mixture of salt, chalk and bones ; small crystals of apa- 

 tite are among the commonest associates of melaphyre. There- 

 fore it cannot be astonishing that apatite occurs in empty veins. 



