AT4 : Scientific Intelligence. 
analyses of rocks by Dr. F. A. Genth and F. A. Genth, Jr. 144 
pp. 8vo, with maps.—Mr. Hall’s volume is one of the most impor- 
tant that has come from the main’ peelaen sedi of Penn- 
one series and none of them older than Lower ; casi The fa cts 
prove that the rocks are a continuation of the Taconic and other 
formations of the Green Mountain region, being similar both in 
lithological characters and stratigraphical relations. 
On. the Relations of the Triassic traps and sandstones of 
the Eastern United States ; by Wu. M. Davis. Bulletin of the 
Mus. Comp. Zool., vol. vii (Geol. series, vol. i), 8vo, pp. 249-309, 
with numerous sections paper is the full memoir on the 
Triassic sandstones and trap of Eastern North America which the 
author promised in his ee of his views given in the last vol- 
ume of this Journal (p. 345). 
The uniformity in features of the long trap ridges in the Trias- 
sic areas of Eastern North America, the trap in all those ofa 
nearly north and south course having a bold columnar front in 
Percival, to regard all as intrusive, but with lateral outflow to 
some di e between layers of sandstone. The*object of Pro- 
fessor Davis’s memoir is s , as the result of his investiga- 
how 
tions, that, notwithstanding this uniformity, part of the trap 
ridges are intrusive, and art overflows covered by beds of the 
sandstone of later origin, which tilting and faulting have put 
into their present positions. He makes the Palisades, on the 
Hudson, East Rock a nd West jock sag near New Haven, = 
reasons which he gives, as one ident of 3 an paseo 
he author’s sections make his views clear to the reader 
his text he is strong in many of his statements as to the co onelu- 
sions from his investigations, but says that in Connecticut much 
observation is still necessary. to decide finally on the origin of the — 
numerous ridges. The writer has made many observations in 
Connecticut bearing on the question at issue, and has no eae 
detected any satisfactory evidence of the overflows. A discus- 
sion of the subject is deferred until further observations can be 
made, ee the tacts, for or against, will be presented. 
As to the origin of the vesicular texture of the amygdaloid the 
ieee hak always held, in agreement with the author, that the 
feature was due to “a decrease of pressure which allowed the — 
aaa — =e vapors to separate from the surface of the 
verfio > that is, if this means a decrease of pressure — 
which allowed re moisture or other material in a8 melted rock : 
