650 RECORDS. 



The minutes of the last meeting of Section were read and ap- 

 proved. 



The following program was then offered : 



A. A. Julien, Note on a Feldspar from the Calumet 

 Copper Mine, Keweenaw Point, Mich. 



E. 0. Hovey, Geological and Mineralogical Notes Gath- 

 ered DURING A Collecting Trip in Russia. 



Summary of Papers. 



The feldspar from the Calumet Mine is of common occurrence 

 in museum-collections and was originally taken by some miner- 

 alogists as a form of leonhardite, but has since been generally 

 recop'nized as orthoclase, although this has not been confirmed 

 by any analysis on record. 



Occurrence. — The specimens described below were gathered 

 from the outcrop of the vein at the Calumet Mine, a few days 

 after its first opening. The feldspar was here abundantly dis- 

 tributed through the cellular brownish material of the amygdal- 

 oidal melaphyre. It lined the sides of the cavities in crusts up 

 to I cm. in thickness, and even completely filled them, thus 

 making red aggregates 5 or 6 cm. in length, united by irregular 

 branching seams in an almost continuous network. The inter- 

 iors of these geodes were often completely filled with white cal- 

 cite, rarely showing minute strings of metallic copper. Else- 

 where the calcite had been partially or entirely removed, 

 showing the drusy surface of orthoclase, here and there studded 

 with green spots and films of malachite and chiysocolla, scales 

 of a white talc-like mineral and of brilliant black hematite and 

 dull films of pyrolusite. 



Bright red rhombs of apparently the same feldspar also occur 

 at the Calumet Mine in the coarse copper-conglomerate, in two 

 associations: ist. They lie enclosed within the brown jasper-like 

 pebbles of quaitz-poiphyiy and felsite-porphyry. These rhombs 

 may vaiy up to i cm. or more in length, and their outlines are 

 often more or less rounded, like those of the associated grains 

 of gray quartz. They have been described by R. Pumpelh' 

 (Geol. Survey Mich., I. (1873), Pt. II., p. 37), who also states, 



