170 The American Naturalist. [February, 
The Marquis G. de Saporta (Annales des Sciences Geologiques, 1889,) 
contributes an article upon the fossil plants of Aix, in Provence, 
studied stratigraphically and paleontologically. The plates illustrat- 
ive of the shells of the Aix group accompany the memoir. 
Additions to the vertebrate fauna of the Preglacial Forest Bed of 
the Norfolk coast increase through the rapid denudation carried on by 
the North Sea, and Mr. E. T. Newton has in the April issue of the 
Geological Magazine described Cervus rectus n.Sp., and recognised 
the presence of Bison bonasus, Phoca barbata, the narwhal, the beluga 
and the porpoise. 
H. H. Howorth, M. P. (Geol. Mag., July, 1889) states his belief 
that in the mammoth age the Arctic Ocean either did not exist, or was 
very small, the greater portion of its area being occupied by land upon 
which trees would grow. The continents would therefore be united 
by land, and an ample bridge provided, This land area would par- 
tially account for the warmer climate. 
MINERALOGY AND PETROGRAPHY.! 
Petrographical News.—In his report on the geology of the 
Rainy Lake region, Dr. Lawson? gives .a petrographical description of 
the rocks comprising the Laurentian, Coutchiching and Keewatin 
groups in the neighborhood of the above-named lake in Canada. The 
rocks of the Keewatin series are principally bedded traps and green- 
stones, altered from traps by metasomatic and dynamic metamorphism, 
and greenstones of clastic origin, hornblende schists and other foliated 
rocks. The effect of pressure is shown in the broken condition of 
many of the crystals in the rocks; crushed and sundered plagioclase, 
apatite, hornblende, leucoxene, tourmaline and quartz are all described 
and figured. Between the hornblende schists and the Laurentian 
gneisses the author recognizes phenomena which he believes to be due 
to contact action. If this supposition is found to be a correct one, the 
fact affords a striking confirmation of the view that the gneisses under the 
1 Edited by Dr. W. S. Bayley, Colby University, Waterville, Me. + 
2 Geol. and Nat. Hist. Surv. of Canada. Annual Report for 1887. Pt. F. 
