314 Scientifie Intelligence. 
ture of the “ Azoic” and the opinions of the paren aac. tle 
ZOIC 
sonable muraect for counter-discussion. The work is a valuable 
addition to the history of American geological science; an 
will be increasingly valued as the discussion of the subject 
at the same time it is fae that the “ Azoic” is not yet proved to 
have been azoic,—is not yet proved to ee probabl y been azoic ; 
it is also true that the Archzan limestones have not been pry 
to be of chemical origin, or to be not of organic origin. The 
dences on both sides are still doubtful evidences; and being) Mi 
it is impossible for most minds to settle down into the positive 
belief that the era was to the end without life or that the ex1s- 
tence of life then was improbable; and hence the adoption of the 
non-committal term Arehwan for the rocks and events of time 
preceding the Primordial—agreeing in limits as far as its pro- 
poser, the writer, understands ogee eaten ang some remarks in 
the volume) with Whituey’s Azo 
e subdivisions of the A suiban are considered in the volume 
at much length and one to be—even that of the Huronian— 
without a “sep grea bas J. D. D. 
4. Thirteenth annual fepen on the Geology and Natural His- 
tory of raesaehag by Joun Coxtett, State seo aaee 161 and 
264 pp: ae with eens fake and a geological m Indian- 
includes an introdution on the ormation of coal and hee seine 
of general interest. esquereux derives from the number of 
species of coal plants Bod in the nodules of the shale at Mazon 
Creek, Illinois and from the same shale elsewhere, that at least 200 
species of plants contributed to the formation of a sin gle bed of 
coal; and adding other species from the same horizon, the number 
