ORE DRP08U 19 



(b) Basic. 



1. Peripheral masses. Copper, iron, nickel. Sul- 

 bury, Ontario. 



2. Dikes. Titaniferous iron. Adirondacks and Wy- 

 oming. 



B. 3. Igneous emanations. Deposits formed from v. 



above or near the critical point, e g., 365 C. and 200 

 atmospheres for H 2 O. 



(a) Contact-metamorphic deposits. 



1. Deposits confined to contact. Magnetite deposits 

 (Hanover, New Mexico); chalcopyrite deposits, 

 Kristiana type; gold ores, Bannock, Idaho, type. 



2. Deposits impregnating and replacing beds of 

 contact zone. Chalcopyrite deposits, pyrrhotite 

 ores, magnetite ores, Canada type; gold tellurium 

 ores, Elkhorn type; arsenopyrite ores, Similkameen 

 type. 



(b) Veins closely allied to magmatic and to Division D. 



1. Cassiterite. Cornwall, Eng. 



2. Tourmaline copper. Sonora, Mex. 



3. Tourmaline gold. Helena, Montana; Minas 

 Geraes, etc. 



4. Augite copper, etc. Tuscany. 



C. Fumarolic deposits. 



(a) Metallic oxides, etc., in clefts in lava. No commercial 

 importance. Copper, iron, etc. 



D. Gas-aqueous or pneumato-hydato-genetic deposits, igne- 

 ous emanations, or primitive water mingled with ground water. 



(a) Filling deposits. 



1. Fissure veins. 



2. Impregnation of porous rock. 



3. Cementation deposits of breccia. 



(b) Replacement deposits. 



1. Propylitic. Comstock, Nevada. 



2. Sericitic, Kaolinic, calcitic, copper-silver, silver- 

 lead. Clausthal, De Lamar, Idaho. 



3. Silicic dolomitic, silver-lead. Aspen, Colorado. 



4. Silicic calcitic. Cinnabar, California. 



5. Sideritic silver-lead. Coeur d' Alene, Idaho; 

 Slocan, B.C.; Wood River, Idaho. 



6. Biotitic gold-copper. Rossland, B. C. 



