570 The American Naturalist. [June, 
and represent several genera. Beautifully preserved specimens of 
Notidanus, Scapanorhyncus (Rhinognathus), Odontaspis, Oxyrhina, 
Otodus, Lamna, and Corax are abundant, and have a wide vertical 
range. The character and extent of the Selachian fauna indicate 
conditions very similar to those accompanying the deposition of the 
English and French chalk, and that of Central Europe generally, 
whilst it affords comparatively few data for comparison with that of 
Lebanon.” 
The Surface Geology of Alaska.—I. C. Russell’s paper on 
the surface geology of Alaska contains some interesting facts on the 
glaciation of that region. He agrees with Dauron and McConnell 
that there is a great area to the north of the Cordilleran glacier which 
was not occupied by ice during the Plistocene. Of living glaciers 
those on the north side of the Coast Range are very much smaller than, 
and do not descend nearly so far as, the glaciers on the south side of 
the same range. Closely related to the distribution of the glaciers are 
certain climatic phenomena. 
_ In the Yukon region the winters are long and extremely cold, but 
the snowfall is not great. The summers, though short, are pleasant, 
and hot enough to melt the winter’s snows. On the southern coast 
the winters are not severe, but the snowfall is heavy on the mountains, 
and the summers are cloudy and hot, with much fog. 
These observations show that abundant precipitation, accompanied 
by a low mean annual temperature (due especially to a cool and cloudy 
: Summer) has resulted in the formation of the vast ice-fields on the 
southern coast of Alaska from which magnificent glaciers descend to 
the sea. (Bull. Geol. Soc. Am., Vol. I., pp. 99-162.) . 
Geological News.—General.—Sir. Wm. Dawson has retained 
the name “Quebec Series” in his recently published hand-book, as 
the name for the Atlantic type of the lower member of the Ordovician, 
: and as equivalent to Upper Calciferous and Chazy of the interior 
region of America. (Canadian Record Science, July, 1890.)—— 
Alexander Somervail offers the theory of ‘segregation’’ as an explan- 
ation of the banded structure of certain rocks in the Lizard District, 
England. By the the term segregation he means the separation of the 
unlike, and the union of like, minerals during the cooling of the 
common magna out of which the rocks are formed. (Geol. Mag.» 
Nov., 1890.) Henry Hicks is of the opinion that the pre-Cambrian 
rocks of Britain contain evidences of successive periods of elevation 
