68 Scientific Intelligence. 
above the present lake-level. These deposits aaah ast least three 
well-defined periods in the history of Lake Lahont sb the 
fi as formed, the lake, then a fresh-water bo ta 
the fossils, filled the basin to within ~— feet of ‘hss highest 
water-line now scoring its sides. Later the water was 400 feet 
lower and it was highly charged with eae Then the thinolite 
ary 
above this terrace and the sate’ tufa deposit was precipitated. 
There were, therefore, two moist periods, when the lake was deep, 
separated by a time of daniedion pa followed by the present 
period of aridit 
Mr. Hague, in “his abstract on the geology of the Eureka Dis- 
trict, iio the Eureka section a thickness of 30 ,000 feet, divided 
: Cambrian, 7,700 feet; Silurian, 5 000 feet ; Devonian, 
8,000 feet, ‘and Carboniferous 9, 300 feet. The mingling of Coal- 
Measure and Lower Carboniferous types is more clearly shown in 
the Carboniferous rocks of the Eureka Basin than in any other 
western locality. 
In the paper on the terminal moraine of the second glacial 
epoch, Prof. Chamberlin not only abstracts the results of recent 
investigations by himself and assistants, but combines therewith 
the observations of others; he e gives a description of a compound 
moraine traced continuously from the Atlantic coast in New En ng- 
land, through New Jersey, Pennsylvania, Ohio, Indiana, ie 
Wisconsin, Minnesota, Iowa, and finally Dakota, where the 
103d meridian, it passes into British America, His ¢ onteinieitia 
. < yee geology is too important to be ies buletly. character- 
, but space ee not permit of more at 
r ©. e’s paper on the a fo fossil Mollusca of 
North America, Aehick concludes the volume, is one of the most 
interesting in it, especially to those who have followed the con- 
troversy as to the age of the Laramie group. The paper is accom- 
panied by thirty-two plates, one of which is devoted to Devonian 
forms, one to sere: ime Triassic, two to Cretaceous, three to. 
the Bear River Laramie, and the remainder to the Laramie ae 
proper. These plates ‘Sikidiuac an annotated catalogue which 1 
a résumé of the subject by zoological families. A tabular view is 
also presented. There is be sides, an introduction which states 
wi 
reference to more than one or two points, Three categories of non- 
marine mollusks are embraced by those of brackish-water, those 
of fresh water, and those of land habitat. Dr. White points out 
: : Bl 
nearly resembled. He also states the conclusion that the mollus- 
can fauna of the present Mississippi system is lineally descended 
from the faunz of the ancie ent lakes and seas of the me and 
