98 SCIENCE 
As an instance typical of that unevenness 
of treatment previously mentioned the genus 
Samaropsis may be examined with some slight 
detail. In Fig. 502 A on page 350 are shown 
three figures copied from Dawson of Sama- 
ropsis fluitans. This species is apparently 
selected for discussion and illustration since 
this name appears in many lists of Carbonif- 
erous fossils from various localities. Dawson’s 
figures are notoriously unreliable, as is very well 
known on this side of the Atlantic, and his 
types of Samaropsis fluitans scarcely deserve 
to be taken up as the types of anything. Now 
if we turn to Samaropsis fluitans as identified 
by Weiss we find that it represents an alto- 
gether different object. Similarly Kidston’s 
and Zeiller’s Samaropsis fluitans, while they 
are identical with one another, can hardly be 
considered as identical with either Dawson’s 
or Weiss’s objects so named and Grand’Kury’s 
Samaropsis fluitans is a still different object. 
Turning to the second species shown in this 
ficure, namely Samaropsis emarginatum of 
Goeppert & Berger, we find that the type 
firures are absolutely unrecognizable. We find 
that Geinitz referred two totally different 
forms to this species, Hoffman & Ryba’s deter- 
mination of it is questionable, Feistmantel’s 
forms of this name are still different, and 
Kadston’s figures of 1902, 1908 and the pres- 
ent work can scarcely be regarded in any single 
instance as representing any of the previous 
determinations. If we turn now to C and D 
of this same figure, supposed to represent Cor- 
daicarpus Cordai of Geinitz we find that 
Geinitz figured a variety of things under this 
name, but he expressly states in his text that 
these seeds are 2 cm. in diameter and some- 
times twice that size and tumid. When we 
turn to Zeiller’s, Kidston’s or Vernon’s figures 
ealled by this name we find a tiny, often flat, 
form, totally unlike anything that Geinitz 
figured. It may also be suggested that H of 
this figure is upside down and that instead of 
having a Samaropsis bicaudata we have a 
Samaropsis bicornuta, for which there are 
analogies in other species of Samaropsis. 
These instances may be taken to illustrate 
my criticism that unsatisfactory forms were 
[N. 8. Von. XLVIII. No. 1230 
selected for figuring in the present work with- 
out any digestion of the subject simply because 
the names occur frequently in the literature, 
a method of procedure which not only entirely 
obscures any chronologic value that these ob- 
jects might have, but crowds out figures or dis- 
cussion of really good material. The case may 
be stated something as follows: The poorer 
the type material of a species the more readily 
will other things be confused with it and so 
in the course of time it is always the least 
recognizable and the poorest types that become 
credited with the greatest range, both geolog- 
ical and geographical. 
This sort of criticism might be legitimately 
applied to many other items in the present 
volume. These are almost always subjects 
outside of Professor Seward’s own specialty, 
and subjects in which I fancy he is not greatly 
interested, and while they do not detract from 
the value or accuracy of that part of the work 
where the author is on familiar ground, an 
author should not pose as an authority on 
phases of work in which he shows tio apparent 
interest or willingness to give the labor neces- 
sary to the mastery of the literature, so much 
of which it is admitted is of minor value. 
For this very reason and the further reason 
previously mentioned of Seward’s attitude re- 
garding what constitutes a fossil species, it 
may be considered very fortunate that the 
author has been unable as yet to carry out 
his intention of discussing the geographical 
and geological distribution of fossil plants. 
Epwarp W. Berry 
Tur JOHNS HopKINS UNIVERSITY, 
Bantimore, Mp. 
SPECIAL ARTICLES 
THE GLASS SANDS OF PENNSYLVANIA 
Atv present in the manufacture of glass, 
nearly pure quartz sands are used almost ex- 
clusively as the source of the silica which is 
the major constituent of all the common va- 
rieties of this useful substance. An ideal 
glass sand would be one made up entirely of 
grains of the mineral quartz. Sands contain- 
ing 100 per cent. silica, however, are not found 
in nature, although some very nearly approach 
