290 The American Naturalist. [March, 
4 
opinions respecting the age of the Vineyard series; plants found at 
various localities in that series; the Gay Head flora cretaceous ; its 
distribution and affinities; mode of occurrence ; eastward extension of 
the Middle Cretaceous ; origin of amber in the Vineyard. Illustrated. 
THE GEOLOGY OF THE Crazy Mountains, Montana. J. E. 
Wolff, Cambridge, Mass.—This paper describes the structure of these 
mountains, which are composed of Cretaceous strata, horizontal or but 
gently inclined, cut by numerous narrow vertical dikes and large 
irregular masses, as well as great bulging intrusive sheets of laccolites, 
which have been tilted with the strata. Brief descriptions are given of 
the eruptive rocks and of the contact metamorphism produced by them. 
THE CuBOIDES ZONE AND ITs Fauna. A Discussion oF METHODS 
oF CorRELATION. H. S. Williams, Ithaca, N. Y.—In this paper, after 
discussion of the principles of correlation, and after comparisons of 
fauna of this zone in Europe and Asia, as well as in America, the 
author comes to these conclusions : 
That the fauna of the Tully limestone of New York is the represen- 
tative of the fauna of the Cuboides zone of Europe homotaxially ; that 
the relations of the two faunas may be best explained by the hypothesis 
that the fauna of the Tully limestone is not a direct sequent of the 
underlying Hamilton fauna alone, but in its characteristic species 
shows evidence of community with European faunas to be explained 
by migration. 
A comparison of all the related faunas at present known leads to 
the conclusion that the Cuboides and Tully faunas are not only homo- 
taxial but relatively contemporaneous, the margin of difference in the 
time of the existence of the two faunas probably not greater than the 
period of existence of the Cuboides fauna in its typical localities in 
Europe 
THE INTERNAL RELATIONS AND TAXONOMY OF THE ARCHAAN OF 
CENTRAL CANADA. Andrew C. Lawson, Ottawa, Canada.—Archean 
comprises two great systems, Lower (Laurentian), composed of plu- 
tonic igneous rocks; Upper, of indubitably normal surface rocks, 
variously altered. Lower, irruptive through Upper and of younger 
age, piercing tie latter, holding: detached fragments from its shattered 
margin, and Conception of Archean 
suggested by the facts : Its ideal simplicity ; ; complication’ ; combined 
effect of plutonic irruptions and crust-crumbling forces. Geognosti- 
cal equivalents of Laurentian elsewhere found to be eruptive, 

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