SYNOPSIS OF PROCEEDINGS. 333 



west under the lake at angles varying from 30° to 60°. Only certain 

 of these beds are copper-bearing. According to the character of the 

 deposits they may be classified as follows : 



1. Conglomerate beds. The copper occurs as cement and partial- 

 ly replaces pebbles. Examples. Calumet and Hecla, Tamarack. 



2. Amygdaloid mines. Copper filling small blow-holes in upper 

 portion of igneous sheet. Example. Atlantic, Osceola. 



3. Irregular masses, often of large size, of copper in true veins at 

 right angles to bedding of strata, with a gangue of calcite, epidote, etc. 

 Example. Copper Falls. 



The first two are of the most importance. Some of the amygdaloid 

 mines furnish a great deal of "mass" copper besides the ordinary 

 ''stamp rock." All the ore, except the masses, is broken by Blake 

 crushers, then crushed by enormous steam stamps, and the copper 

 concentrated on jigs, tables, etc., to about 80 per cent. The concen- 

 trated mineral and pieces of mass copper are then melted down and 

 refined in reverberatory furnaces, and cast into ingots of unrivaled 

 purity. 



The specimens are as follows: 



Amygdaloid Ore, from the Atlantic and Osceola mines. Native 

 copper in melaphyr gangue. Average of Atlantic ore is .66 per cent, 

 copper, and of Osceola i J-4 per cent. 



Trap, hanging wall of Atlantic mine. 



Sheet Copper, Osceola mine. 



Shot Copper, Osceola mine. 



Native Copper, Osceola mine. 



Conglomerate, two specimens, coarse and fine, from the Tamarack 

 mine. This mine is working the same vein as the Calumet and Hecla. 



February 23, 1894. Benjamin R. Putnam. 



June 2g, 18^4 — Regular Meeting. 



President Allen in the chair ; six members present. 



The Curator reported the receipt of a number of mounted ornitho- 

 logical specimens from Dr. S. Bowman of Bennett, Iowa ; also from 

 Mr. G. H. Hinrichs of this city, a post or log of wood bored by te- 

 redos and thickly covered with barnacles. This specimen was ob- 

 tained by Mr. Hinrichs during a recent visit to Florida. 



The following resolutions of respect were presented and adopted : 



Resotved, That in the death of Rev. S. S. Hunting, which occurred at 

 Des Moines, June 2, 1894, this Academy has sustained the loss of an hon- 

 ored hfe member and former president, and of a co-worker whose energy 

 and enthusiasm were ever helpful and inspiring throughout the time of his 

 resident membership. In him the world has lost a true man — honest, fear- 

 less, strong ; one who did his duty and sought the light, untrammeled by 

 prejudice or tradition. We honor him for the invaluable example of a life 



[Pkoo. D. a. N. S., Vol. VI.] 42 [February 13, 1897.] 



