330 Scientific Intelligence. 
Notes on the Geology of the Iron and Copper Districts of 
ele Supeitor ; by M. E. Wapsworru. a July, 1880. 
158 pp. 8vo, ‘With six plates. Bulletin of Museum of 
Comparative "Zoolo ogy at Harvard College, Vol. vu (Geological 
Series, Vol. 1).—The author devotes 76 pages of his memoir to 
ography of his subject. Under each head a large part of the 
space is devoted to an como review, giving the opinions and 
statements of authors in chronological order and lar ely by cita- 
tions from their works. He quotes freely from the valuable Report 
on the Lake Superior District by Foster and Whitney, and in the 
main supports the views which Prof. Whitney had there brought 
out. 
He makes the iron ores and associated beds of jasper intrusive. 
ney, are prono eonted to be of the age of the Potsdam sandstone ; 
or a conclusion is not based on the author’s personal observa- 
The kinds of copper deposits in the Portage Lake and Kewee- 
naw Districts are stated to be as follows: Ist, The dort bape oe 
variety of the Amygdaloid Mines, called in the region “ ashbed ” 
mines, are said to differ only in this that the amygdaloid is of a 
scoriaceous “eect The Copper Falls and the Atlantic Mines 
are of —. ure. 
Bes can, * there are, secondly, Conglomerate or true bed 
mines, like the Calumet and Hee la; and, thirdly, true Pisswre-vein 
mines, like the Central, Phesir and in part the Copper Falls. 
In the Conglomerate mines, the beds of conglomerate have 
places filled with copper. At the Calumet and Hecla mine, which 
is of this kind, the copper is found filling the joints of the over- 
lying tt ang and extendin ng as a continuous sheet in fissures at 
es to one another. 
daloid ; and “these are analy “ong at ake appe er end and 
pointed at the lower.” In the veins, “the copper is found inti- 
mately mixed with the gangue, or in ‘sheets or irregular masses ; 
and the masses often enclose quartz, calcite and other kinds of vein 
materials, beside portions of the trap. “The farther from the sand- 
stone and the nearer the heavy beds of trap, the larger have been 
the deposits of ate ” as is exemplified at the Central, Cliff, and 
Calumet and Hecla mines. 
The author holds that the copper and the associated minerals 
