12 



L. H. Boryströni. 



(LVII 



pegmatite-dikes (and Iheir equivaleiits amoiig the quarzveiiis), 

 lormed at a considerable depth below the surface. The 

 molybdeiiite is qiiite common iii some of the with graiiitic 

 magma connected cassiterite-wolframite-ores. These are 

 partly related to the pegmatiteveins partly typical piieii 

 matolytic prodiuts. The formation of the latter has seem- 

 ingly combined a high temperature with a — compared to 

 this temperature — small depth. 



The antimonyoxysulphide, the kermesite, is a common 

 secondary mineral in the upper niveaus of antimonymiiies. 

 It is here associated with arsenicoxides and other oxyde- 

 minerals, which are formed through the effect of oxygen 

 from the atmosphere. The formation of the kermesite is 

 thiis bound to the immediate neiahbourhood of the surlace, 

 and the occurrence of the mineral seems to be limited to 

 only the outmost part of the already — because of the low 

 meltingpoint — narrow zone of the earths crnst, in which 

 it may be able to exist. 



The table above is a summary of the data concerning 

 the existence and formation of the metalloid-sulphideminerals 

 which have beeii recorded in this paper. It shows a very 

 pronounced analog\ between the meltingpoint of the minerals 

 here considered, and the depth below the surface of the 

 earth, at which they probably are formed. With assistance 



