164 Recent Literature. [ February, 
the correct one. The Archzean limestone and iron-ore beds of 
ew York are likewise considered to be Huronian.” 
do thousands. Even in the more extended views presented i" 
this sketch, relative injustice is done the earlier eras. In discus 
ing the Laurentian, measuring as it does accumulations may 
thousands of feet in thickness, we only consider it as a WI a 
making no attempt at even an enumeration of the subordin; 
periods of deposition that marks its history. Even in des thick 
the Huronian system we barely enumerate the successive t 
deposits, though they embrace rich and varied accumulations "i — 
ore, carbon and lime, besides common detritus. Were these be 
modified members of the later systems, they would doubtless 
tanked as important periods, and the whole Huronian Sy°" 
would be graded as the equivalent of the Devonian age, or per 
haps of the Mesozoic era.” 
the Wisconsin and adjoining areas. Two glacial epochs are n 
scribed, their existence clearly proven, and the colored m 
tions or theoretical maps of the two periods will be foun eart 
most useful and timely. We have nowhere met with a < prodl : 
and more comprehensive exposition of the subject, and j P 
Whitfield, Professors L. C. Wooster and F. By 
others. As they stand, the four volumes of this survey *® < 
notable addition to our geological literature. 
U. S. Fish Commissioners’ Report For 1880)—The of jut 
reports of the U. S. Fish Commission reach us each year, = ’ 
1U. S. Commission of Fish and Fisheries, Part VII. Report of the Commis i i : 
[S. F. Baird] for 1880. Washington, 1883. 8vo, pp. 1060. 
