364 



SCIENCE. 



[N. S. Vol. V. No. 113. 



currence of native copper and other copper 

 minerals in the hematite ore of the Montana 

 Mine, Soudan, Minnesota. The copper occurs 

 in a thin seam and, in smaller amount, in cavi- 

 ties of the fractured ore. The original mineral 

 of the group is native copper. This has been 

 altered extensively to cuprite, malachite and, 

 in more limited quantity, azurite. These 

 minerals are found penetrating the ore for a 

 distance of five or six feet below the seam and 

 horizontally for a distance of eighty feet. 

 None of the secondary minerals occur above the 

 native copper. All the minerals are exception- 

 ally pure. Some specimens of the copper show 

 former crystals, the faces of which are now 

 heavily coated with secondary products. 



Attention was called to the very unusual as- 

 sociation of these minerals. So far as the 

 writer is aware, no similar occurrence has been 

 recorded from the iron mines of the United 

 States. 



The second topic included several charts il- 

 lustrating the glacial geology in the vicinity of 

 Taylor's Falls, Minnesota. At this place the 

 line of separation between the so-called eastern 

 and western drift is very sharply defined. The 

 course of the St. Croix river seems to be de- 

 termined by the mutual adjustments of the 

 eastern and western ice lobes. The moraine 

 made up of typical eastern drift forms a close 

 border along the east bank of the river for 

 several miles, while typical modified western 

 drift borders the west bank and, in at least one 

 point, crosses the river. The combined effect 

 is to force the river over the southwestern 

 extension of the copper-bearing diabase of 

 Keweenawan age exposed in this vicinitj^. It 

 was further shown that the eastern drift occurs 

 both below and above the western, arguing a 

 readvance of the eastern lobe of ice upon the 

 area of the receding western sheet. It was 

 also shown that partially stratified early drift 

 occupies a position so far below the average 

 elevation of the sandstone surface in the pres- 

 ent river gorge that it seems to indicate the 

 location of a pre-glacial stream course at this 

 place. Glacial action simply deepened this 

 course and made it more permanent by direct- 

 ing through it a great glacial river. It was fur- 

 ther pointed out that the original topography 



of the country was such that any flow of ice 

 from the north or northeast would concentrate 

 exceptional eroding force in the gorge of the 

 St. Croix in the vicinity of the present falls. 



JANtrARY 30TH, 1897. 



At this meeting Mr. George W. Becker re- 

 viewed some of the points in the geology of 

 northern Georgia. Facts derived from personal 

 observation upon a recent visit to that locality 

 were discussed at some length. These related 

 chiefly to the methods employed in gold min- 

 ing, to the value and extent of the asbestos 

 deposits of Yhona Mountain, and the occur- 

 rence of corundum in northern Georgia. 



Charles P. Berkey, 



Secretary. 



NEW BOOKS. 



Zeit-und Streitfragen der Biologie. OscAR Hert- 



wiG. Jena, Gustav Fischer. 1897. Heft 



II. Pp. iv+277. 

 Beitrage zur Kenntnis der Septalnectarien. J. 



SCHBLWIND Thies. Jena, Gustav Fischer. 



1897. Pp. 87 with 12 plates. 15 M. 

 Beitrage zur Lehre von der Fortpflanzung der 



Geivdchse. M. MoBius. Jena, Gustav Fischer. 



1897. Pp. viii -1-212. 4.50 M. 

 Kainogenesis als Ausdruck differenter phylogene- 



tischer Energien. Ernst Mehnekt. Jena, 



Gustav Fischer. 1897. Pp. 165 with 3 



Angeivandte JElektrochemie. FrANZ Petbrs. 

 Vienna, A. Hartleben. 1897. Pp. 338. 3 M. 



The Forcing Book. L. H. Bailey. New York, 

 The Macmillan Company. 1897. Pp. xiii-f- 

 266. $1.00. 



Analysis of the Sensations. Ernst Mach, trans- 

 lated by C. M. Williams. Chicago, Open 

 Court Publishing Company. 1897. Pp. viii+ 

 208. $1.25. 



Eclairage. J. Lefevbe. Paris, Gauthier Vil- 

 lars et fils, Maason et cie. 1897. Pp. 180. 



Les swccedanes du chiffon en papeterie. Paris, 

 Gauthier Villars et fils, Masson et cie. Pp. 

 173. 



Glaciers of North America. I. C. Eussell. Bos- 

 ton, Ginn & Co. 1897. Pp. x-|-210. 



