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JuLy 26, 1918] 
doxylee, Calamopityer, Cladoxylee and Pro- 
topityes, and these are discussed in a separate 
chapter under the group term of Cycadofilices. 
These presumable pteridosperms, because of 
the dearth of conclusive evidence, are thus 
arbitrarily segregated. While caution is to be 
commended in dealing with fragmentary plant 
fossils it may be questioned whether judg- 
ment may not be suspended until it dies of 
inanition. It is also questionable how far it 
is desirable to introduce purely artificial 
groups, and if it be granted as desirable, it 
may be pertinent to ask what criteria are to 
decide such a question. That such a course 
does not make for clearness and that such 
questions rest after all upon personal equation 
rather than upon objective facts may be illus- 
trated by Seward’s reference of the genus 
Steloxylon to his Pteridosperme and the 
scarcely to be distinguished genus Cladoxylon 
to his Cycadofilices. The fact that so many 
of the so-called families of the latter group are 
monotypic is convincing enough evidence that 
they illustrate chance discoveries and the im- 
perfection of the geological record and that 
they have absolutely no other significance such 
as Scott has suggested. 
Following the chapter devoted to Cyeado- 
filices are two chapters dealing with the 
Cordaitales which are described under the 
three groups of Poroxylee, Cordaitee and 
Pityee. A succeeding chapter of 65 pages is 
devoted to Paleozoic gymnospermous seeds and 
the remainder of the book is taken up with a 
consideration of fossil Cycadophytes. These 
last chapters are, on the whole, a very satis- 
factory summary of the present state of our 
knowledge although the concluding chapter, 
devoted to the fronds, is much abbreviated and 
not especially noteworthy. 
There can be no doubt of the usefulness of 
Seward’s book, particularly in the case of 
mature students and professional morpholo- 
gists. The author has a wide acquaintance 
with the literature, especially on the side of 
morphology and modern botany, and the book 
shows throughout the results of considerable 
original work and a large amount of reinvesti- 
gation of insufficiently described material of 
SCIENCE 95 
older workers. It may seem ungracious to 
criticize a noteworthy undertaking but it seems 
to the reviewer that throughout the three vol- 
umes already published there is a disregard of 
proportion and an unevenness of execution 
that seriously impair their value. It is im- 
possible to discover the method of selection of 
matter to be included—unimportant and even 
doubtful forms are sometimes discussed, as 
under Williamsonia, among the seeds, or the 
frond genera of Cycadophytes, while more im- 
portant material is not even mentioned. In 
a work spreading through four stout volumes 
one reasonably expects either completeness or 
a formulated method of selection. If the de- 
sire was to present in the main fossil plants 
based upon structural materials, why burden 
the pages with a very incomplete representa- 
tion of other classes of plant remains. 
The author assumes an oracular air that 
reminds one of Lowell’s charming essay en- 
titled “ On a certain condescension in foreign- 
ers,” and there is constantly displayed a readi- 
ness to pass judgment merely on the illustra- 
tions of other students’ work, often in cases 
where most paleobotanists would be disposed 
to deny the author’s competency, as for ex- 
ample in the case of the determination of 
American species referred to Hremopteris. 
There are also certain insular tendencies, as 
in the overemphasis of Carboniferous, Jurassic 
and Cretaceous horizons that have been studied 
in Britain, and the space devoted to the local 
history of important British specimens. 
Professor Seward’s position on the difficulty 
of founding well-marked botanical species on 
material preserved as impressions is well 
known and in the main sound. However, as 
has been pointed out recently by Halle, this 
does not justify the assumption that all fossils 
that are superficially similar belong to the 
same species regardless of geographical posi- 
tion or geological horizon. Such a method of 
treatment entirely obscures whatever real value 
such fossils may have for purposes of deduc- 
tion concerning geographical distribution, the 
problems of paleogeography growing out of 
distribution, and the bearing of fossil plants 
upon stratigraphy. 
