Geology and M ineralogy. 73 
tutes a valuable contribution to the detailed paleontology of the 
upper Mississippi valley area. 
In the chapter on the Cretaceous Flora by Leo Lesquereaux, 
the author remarks upon the impossibility of explaining the sud- 
den appearance in the Dakota fauna of the rich dicotyledonous 
flora by any gradual modification of the floras known from earlier 
epochs. ‘‘ No species of the dicotyledonous series has as yet 
shown any such intermediate characters indicating by its infer- 
iority a degree of transition: nor has there been found in the 
series of lower divisions of plants occurring below any whose 
characters would indicate a tendency to a transition to a higher 
order.” The flora collected in this limited area from only three 
localities contains 28 species, only two of which are gymnosperms. 
And the dicotyledonous species are referable to 18 genera, and 
to the three great subdivisions of the dicotyledons ; the Apetalee, 
the Gamopetalee and the Dialapetalec. 
Cretaceous foraminifera are described: by Messrs. Woopwarp 
and Tuomas, the sponges, graptolites and corals of the Lower 
Silurian by Messrs. N. H. WincuELt and ScuucueErt, and the lar- 
ger part of the volume is devoted to “ Descriptions of the Lower 
Silurian Bryozoa” by E. O. Uxricu, and the ‘‘ Lower Silurian Bra- 
chiopoda” by Messrs. N. H. WincuEezyt and Cas. ScHUCHERT. 
The annual reports contain, among other papers, a critical ex- 
amination of Dr. Williams’ discussion of the greenstone schists of 
the Menominee and Marquette region of Michigan (Bull. U.S. 
G. 8. No. 62), by N. H. Wincuet1z, who defends his previously 
expressed opinion “that the great bulk of the ‘ greenstones’ as 
an Archean terrane, ought to be classed as pyro-clastic, i. e., that 
they originated from eruptive agencies, as tuffs and all kinds of 
volcanic debris, sometimes very coarse and even distributed and 
somewhat stratified by the waters of the ocean into which the 
materials fell.” A preliminary report on the Rainy Lake gold 
region is given by H. V. Wincouett and U. 8. Grant. Warren 
Upuam gives in the latter report the evidence derived from the 
beaches of the various glacial lakes in the St. Lawrence basin; 
following a paper, in the previous report, in which occurs a detailed 
account of the glacial drift and morains of northeastern Minnesota. 
H. S. W,. 
3. Doctorate Theses in Geology.—Two theses by Americans 
studying geology in European universities have been received, 
VIZ 
Die Klippen region von Iberg (Sihthal), von Dr. Epmunp C. 
QueEREAU aus Aurora, Ill., 4 geol. charts, 4 profile plates and 
13 zinkographs, pp. i-xi and 1-158, Bern, 1893.—This paper con- 
stitutes the 33d number of the Beitrage zur Geol. Karte der 
Schweiz. 
Beitrige zur Kenntniss der Gattung Oxyrhina mit besonderer 
Beriicksichtigung von Oxyrhina Mantelli Agassiz, (Palaeonto- 
graphica, Bd. xli, pp. 149-191, Taf. xvi—xvii, Stuttgart, 1894) von 
Cuas. R. Eastman, Assistant an dem Museum Comparative Zo- 
ology, Cambridge, Mass. 
