Mineralogy of South America. 



137 



of which is not yet examined into, and which may be metallic 

 iron (stated by Andrews to be present in the rock of the Giant's 

 Causeway), or possibly magnetite or magnetic titanoferrite. 



The zeolites, Chabazite, Laumonite, Prehnite, scolezite, and 

 stilbite also occur, either in this basalt or at its junction with 

 the oolitic porphyrites. 



(6) Minerals of the Post- Oolitic Diorite Eruptions, with their 

 accompanying Metallic Veins. 



The diorites themselves are composed only of felspar and 

 hornblende when normal, and never contain quartz, unless in 

 localities where they have broken through quartzose strata, and 

 in so doing may have taken up some quartz at points close to 

 the junction. I cannot state what exact felspar or felspars are 

 to be regarded as normal constituents ; but albite appears to be 

 frequently present : the hornblende varies from dark green-black 

 to light green; and occasionally even white (asbestos) appears as 

 a constituent. These eruptions are far the richest in associated 

 minerals ; and we find the following species of primary mine- 

 rals : — 



Akanthite. 



Algadonite. 



Alisonite. 



Amalgams. 



Antimonial silver. 



Antimony. 



Apatite (chlor-). 



Arquerite. 



Arsenic. 



Arsenide of silver. 



Arsenide of silver, 



iron, and cobalt. 

 Arsenio-antimonide 



of silver. 

 Barnhardite. 

 Barytes sulphate. 

 Bismuth. 

 Bismuthine. 

 Bournonite. 

 Chalcopyrite. 

 Chloanthite. 

 Cinnabar. 

 Cobaltine. 

 Colophonite. 

 Copper nickel. 

 Copper (native). 



Copper glance. 

 Copper (sulpharseni- 



ate). 

 Cuban. 



Cupr oplumbite . 

 Danaite. 

 Darwinite. 

 Discrasite. 

 Domeykite. 

 Enargite. 

 Erubescite. 

 Fahlerz. 



Fahlerz (mercurial). 

 Fieldite. 



Fluor-spar (traces). 

 Galena. 

 Glaucodote. 

 Gold. 

 Graphite. 

 Guayacanite. 

 Haematite. 

 Homocline. 

 Iron-pyrites. 

 Iron glance. 

 Leucopyrite. 

 Magnetite. 



Marmatite. 

 Marcasite. 

 Mercury. 

 Miargyrite. 

 Mispickel. 

 Molybdenite. 

 Polybasite. 

 Proustite. 

 Pyrargyrite. 

 Rammelsbergite. 

 Realgar. 

 Silver. 



Silver (bismuthic). 

 Silver glance. 

 Smaltine. 

 Stephanite. 

 Stibnite. 

 Stromeyrite. 

 Taltalite. 

 Tannenite. 

 Tennantite. 

 Tetrahedrite. 

 Zincblende. 

 Zincblende (plumbi- 

 ferous). 



And from the subsequent alteration and mutual reactions of the 

 above under the influence of air, fresh and salt water, we find 

 them associated with the following secondary minerals : — 



