March 9, 1894. 
method that we owe the striking generalizations of Neu- 
mayr and the philosophical views of Suess. Probably 
this distrust with which comparative geology is regarded 
by some scientists is due to the confusion of comparative 
geology proper with the efforts made by some ‘‘ pigeon 
hole” geologists to bring together the formations in 
different widely separated quarters of the globe, and to 
illustrate in convenient tabular form their relations and 
equivalence. Opinions differ so widely regarding these 
correlations that probably no such table of equivalence 
could ever be constructed which would satisfy more than 
its author. Wedo not mean that such attempts are 
wrong in principle, but that they fail of scientific treat- 
ment and are necessarily blind to all that would throw a 
doubt, or disturb their harmony or proportion. 
Comparative geology, as a science, however, is far from 
drawing such definite lines; it rather seeks to indicate 
the possibility of such equivalence and discusses not only 
the facts relative to the important questions of fauna and 
flora, but also marshals into place the physical features of 
structure and of inorganic grouping as well as of geo- 
graphical relations. Not that Dr. Kayser has omitted 
tables of stratigraphical divisions, but these have been 
composed with greatest care and with the best under- 
standing of the difficulties as well as of the facts which 
make the tabulated statement at the same time both 
desirable and to a certain extent possible. 
Dr. Kayser’s ‘‘ Lehrbuch” appeared in 1891, and was 
immediately accepted by German geologists as a most 
important addition to their literature, and since that time 
has been universally regarded as the standard work upon 
the subject. The original work, which was intended for 
the use of German students, was naturally largely devoted 
to the study of the German formations, but even with 
this preference clearly marked there was yet more detail 
of extra German countries than had been usual in previous 
writings. Nor is this particular attention to Germany 
necessarily a fault, as in that country most detailed study 
has been given, and no special locality could have been 
better chosen as an illustration of continental Europe as 
a whole. Moreover, the author’s intimate personal know- 
ledge of the localities described gives additional satisfac- 
tion to the reader. Professor Lake, with a full realization 
of the peculiar insular seclusion of British geologists, has 
appreciated the value of this work to his fellows and in 
giving even a pure translation would have contributed a 
book of greatest value. He has done more than this, 
however, in his many additions descriptive of countries 
outside of Germany, particularly, of course, in treating of 
England, where, as in the former country, the geological 
series have been most carefully worked out. These addi- 
tions are particularly numerous in the early portions of 
the work, becoming somewhat more limited in the discus- 
sion of the later formations, owing to the exigency of 
space. Doubtless in a second edition the writer will be 
permitted by his publisher to develop the work in proper 
proportion. As regards the American formations, the 
comparisons, though brief, are carefully drawn from our 
best authors, and the data are quite sufficient for their 
purpose. Further, as has been suggested in a recent 
review of this same work by Prof. R. D. Salisbury, data 
concerning American geology are more easily accessible 
to American students, thanks to the correlation essays of 
the United States Geological Survey, than data concern- 
ing European geology, which this volume supplies.  Par- 
ticularly is this true of the literature relating to the 
geology of the continent, which appears without excep- 
tion in languages foreign to us and consequently difficult 
for reference. 
1“Lehrbuch der Geologischen Formationskunde,’’ Dr. Emanuel Kayser, 
Ferdinand Enke, 1891. 
Stuttgart, 
SCUAINCIS, 
ES 
Dr. Kayser is fortunate in his translator, Professor 
Lake, who has already attained a high position by original 
work in the same field, both at home and abroad, in con- 
nection with the Geological Survey of India. Mr. Lake 
has aimed to edit as well as to translate and together 
with the hearty codperation of the author has brought the 
book fully up to date, at the same time introducing an 
extension of field, as has been indicated. In points of 
variance between continental and English teachings a 
review of the divergent tenets has in most cases been 
given, and where exceptionally unqualified statements 
have been made, though we may not be in full accord 
with the author, we must at least acknowledge that these 
statements represent the beliefs most widely accepted by 
the geologists of to-day. 
We can give but a brief review of the contents of this 
volume, merely indicating the general treatment of the 
subject. An introduction defines the subject and_ its 
sub-divisions, the classification of the sedimentary strata, 
with a few words on the origin and early condition of the 
earth. Part I. treats of the Archean or primitive rocks, 
their general character, mode of occurrence, origin, etc. 
The importance of this great group is fully recognized, 
though the space devoted to its discussion is rather 
limited. Vhe Palaeozoic or ‘‘ Primary Group” is dis- 
cussed in Part Il., the order of discussion being that 
adopted throughout the work for each group and for each 
system, namely, after general remarks an_ historical 
summary, followed by a study in geographical grouping, 
of development and paleontology. It is in the treat- 
ment of the Palaeozoic that the translator makes his 
greatest departure from the author, rejecting, here, the 
latter’s division into the Cambrian and Silurian systems 
in favor of the English divisions of Cambrian, Ordovician, 
and Silurian. ‘The Silurian of Lake, as is the custom of 
English writers, extends to the top of the Salina, or 
Waterlime, series, the Lower Helderberg and Oriskany 
being included in the second system of the Paleozoic, the 
Devonian. 
The illustrations, which have been drawn in all cases 
from the original work, include seventy-three plates and 
seventy figures in the text, or, inall, 596 illustrations, and 
these form an invaluable part of the volume. The 
majority of these, which are all well executed, are devoted 
to paleontological subjects, but we have also many 
illustrations of structural and physical conditions. The 
typographical work is excellent, the choice of type, 
following the German edition in plan, is such as to bring 
out at a glance the subject matter of each paragraph and 
thus to add greatly to the value of the volume as one of 
reference. This is a matter often either neglected by 
the author or unsatisfactorily accomplished by the pub- 
lisher, and it is rare that we find so carefully executed a 
plan as is here observed. 
Ledward Livingston Youmans; a Sketch of His Life. By 
Joun Fisker. New York, D. Appleton and Co. $2. 
Tuts is a book which all who are interested in the 
diffusion of scientific knowledge among the people, and 
especially all who knew Youmans personally, will like to 
read. It is written in the clear, smooth style of which 
Mr. Fiske is master, and as he was one of Youmans’s 
most intimate friends, the biography has the authority 
as well as the interest which personal acquaintance 
gives. The most interesting chapters to us have been 
the earlier ones, which relate the story of Youmans’s early 
life, his work on the farm and his struggles to obtain an 
education. Then follows the pathetic account of his 
blindness, which, though most of the time only partial, 
