ECONOMIC GEOLOGY 
II. Primary Disseminations and Replacements— 
{@) Disseminations. Monte Catini. 
(6) Replacements in limestones and tuffs. Chillagoe. 
(¢) Replacement—Contact lodes. Tuscany; Oslo 
(Kristiania). 
(d) Pyritic masses in shattered 
Mt. Lyell; Mt. Morgan; 
melsberg. 
Sect. B. SecoNDARY ORES— 
III. Secondary Enrichments— 
(a) Chalcocite bodies. Butte. 
(B) Over -disseminations and replacement bodies. 
Arizona. 
(c) Of sedimentary ores. Katanga. 
IV. Bedded or Sedimentary Ores due to Redeposited Alluvial 
Ores— 
(a) Mansfeld; Cheshire. (Also Chile.) 
(5) Redeposited ores in conglomerates and amygda- 
loids. Michigan. 
ed 
A. Primary ORES 
PnEUMATOLYTIC LODES—ROSSLAND, SOUTH AUSTRALIA, 
AND BraDEN Ming, CHiLE—The two divisions of the primary 
lodes are due to solutions acting at different temperatures 
and depths. Pneumatolytic lodes are formed at the higher 
temperatures and are associated with tourmaline or fluorides. 
Thus at Svartdal, in Norway, the ore occurs with tourmaline 
in a granite of which the felspar has been replaced by quartz 
and mica, Copperopolis in Oregon owes its name to ore 
with tourmaline in diabase. The ore of Vogtland, in Saxony, 
was due to fluoric acid and is in thick veins of fluorite with 
occasional tin. 
At Rossland on the southern border of British Columbia 
(C. W. Drysdale, G.S. Canada, Mem. 77, 1915), another 
lode-type has been formed in a massif of monzonite. The 
lode minerals include much biotite and a little tourmaline, 
with copper, gold, and nickel. The lodes are often 25 feet 
thick, and have in part replaced the walls. The lodes were