May 10, 1912] 
The paleontology fills the remaining five 
sixths of the volume and comprises reports on 
the Molluska by Clark, the Vertebrata by 
Lull and the Plants by Berry. The mol- 
luses are unimportant, consisting of only five 
species, all new, four of which are from the 
Arundel and one—a Unio—from the Patapsco. 
They are of little or no value in correlation. 
The vertebrate fauna—found only in the 
Arundel—is much larger and consists of 
seven genera of dinosaurs, a crocodile, at least 
one turtle, and a ganoid fish. In discussing 
the affinities of the dinosaurs Professor Lull 
compares them with the Morrison of the west 
and the Wealden and Jurassic of Europe, con- 
eluding that “the weight of evidence would 
seem to place this fauna beyond the Jurassic 
into the beginning of Cretaceous times.” As 
the Arundel reptiles are closely related to, if 
not in some cases actually identical with, 
those from the Morrison of Colorado, their 
bearing on the age of the latter is of import- 
ance. ; 
The major portion of the volume is devoted 
to the elaboration of the fossil flora by Mr. 
Berry. As a preliminary to the correlation of 
the Potomae flora he devotes a chapter to the 
“Lower Cretaceous Floras of the World,” in 
which is reviewed the plants of this age in 
Switzerland, Portugal, France, England, Bel- 
gium, Germany, Saxony, Africa, Peru, Japan, 
China and Spitzbergen, as well as the several 
approximately contemporaneous deposits in 
this country. Complete lists of the species oc- 
curring at each locality are given, and while 
no attempt has been made to revise the nomen- 
eclature or determinations, they furnish an ex- 
ceeding valuable basis for correlative and 
stratigraphic comparisons. Following this is 
a chapter on the “ Correlation of the Potomac 
Formations.” In this it is shown that the 
Patuxent and Arundel formations on the 
basis of their contained floras are essentially 
a unit of early Cretaceous age whose affinities 
all lie with the floras which preceded them, 
while the Patapsco, which was separated by a 
long time interval, has its strongest relations 
with the floras which followed it. The con- 
clusion is reached that the Patuxent and 
SCIENCE 
747 
Arundel formations “considered as a unit 
represent all except possibly the earliest part 
of the Neocomian and all of the Barremian of 
standard European sections.” In this country 
it is believed to correspond in whole or in 
part with the Trinity of Texas, the Lakota of 
the Black Hills, the Kootenai of the Rocky 
Mountain region and the Cretaceous portion 
of the Knoxville of the Pacific Coast. The 
Patapseo is correlated with the European 
Albian and with the Fuson of the Black 
Hills. It is chiefly remarkable for the fact 
that it appears to have witnessed the intro- 
duction of the dicotyledons. 
Over four hundred pages and seventy-five 
plates are devoted to the elaboration of the 
flora, which, according to Mr. Berry, comprises 
144 species distributed among the several 
groups as follows: Filicales 43, Lycopodiales 
1, Equisetales 2, Cyeadophyta 33, Ginkgoales 
1, Coniferales 29, Angiosperme 25, of un- 
known systematic position 10. The treatment 
throughout has been conservative and ra- 
tional, and has been based on all of the orig- 
inal material as well as a vast amount of re- 
cently and carefully collected material, with 
the result that the number of recognized 
species has been greatly reduced. Thus, 
Fontaine referred 42 species of ferns to the 
living genus Thysopteris, but these have been 
reduced to 5 and all referred to Onychiopsis. 
The number of species of Cladophlebis has 
been much reduced, as they have in the gen- 
era Abietites, Sphenolepis, Arthrotaxopsis, 
and especially Sequoia. A new generic type 
of fern, thought possibly to be referable to the 
Matoniacex, has been established for certain 
fronds of medium or large size and pseudo- 
dichotomous habit. Another fern, originally 
referred to Baieropsis, is shown clearly to be 
a member of the Schizeacex. 
However, most biologic interest centers in 
the angiosperms, since they are as old as any 
of which we have definite knowledge. From 
the original descriptions and roughly prepared 
figures, it appeared that they were crude and 
archaic as befitted their first appearance, but 
with newer and better material and improved 
methods of reproducing them, they are seen to 
