148 _— Seientifie Intelligence. i. 
among whieh agents are heat and moisture, the former of almost. 
indefinite amount, and the latter in large ‘subterranean suppl 
toward the surface if not abundant below. This “ subterranean 
” must have been pe epics in the 
Prof. Chamberlin discusses the subject of the erosion of Paleo- 
zoic formations in Wisconsin, with interesting conclusions. Speak- 
_ ing of the valley of the Mississippi, he observes that at La Crosse 
now runs, according to an artesian boring in the gravel, at 
eet ay feet above its ancient bed. The basin of Lake Superior 
made a geosynclinal trough (the bottom now 400 feet below 
the adsve formed in the period of the Keweenaw formation, 
though more or less modified Phas tracted by erosion. Lake 
fd a oat bottom of mud now 300 feet below the ocean level 
vast aeletut of pions but not wholly a result of erosion 
‘ ; : see 
e ages) a very full account of the ore deposits in southwestern 
Jisconsin. It will be read with great interest in connection with 
the Missouri Report on the same general subject by Adolf 
Schmidt. The author, after an account of the observations of 
Dr. Percival in 1854-1855, and of J. D. Whitney in 1859, treats 
first Of the ores that were original to the beds—the “hare 
iron carbonate , hematite and limonite ; coppe r carbonates ; with 
py ohasita and gypsum. The forms and constitution of the ores 
are treated of, the distribution of the ore deposits, with map 
illustrations, the origin of the cavities which contain the deposits, 
and the conditions under which the were made. He points out — 
that from Lake Superior to southern Illinois the feeble flexures oF 
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and origin of the cavities. The relations of the ores 
d the changes in them since their deposition are also reap oe 
The theory of origin supposes that the deposits were made by 
oceanic waters, which owed their metalliferous salts 
