Reviews—W. C. Brogger—On the Silurian of Sweden. 316 
abundant Sponge and Radiolarian fauna in a geological horizon where 
these organisms were previously unknown. The Sponges constitute 
distinct beds very similar to those which occur in the Lower and 
Upper Greensands and most of the spicules are closely allied to those 
present in these newer deposits. The Radiolarians, if we except a 
few forms described by Pantanelli from the Upper Lias strata of 
Tuscany, have been scarcely recognized below the Chalk, and yet 
they appear in these Lower Lias deposits, in great variety of form, 
and can nearly all be included in those family divisions which 
Haeckel has constituted for the existing members of the class. 
The descriptions, measurements, and figures of these microscopic 
organisms are given in great detail, and we are enabled to add, from 
a comparison with specimens which have been kindly presented to 
us by Prof. Zittel, with faithful accuracy. G. J. 
JiI.—Die sinurtscuen Eracen 2 unp 5 1m KRISsTIANIA GEBIET 
UND AUF EKER, IHRE GLIEDERUNG, FossILIEN, SCHICHTENSTOR- 
UNGEN UND CoNTACTMETAMORPHOSEN. Von W. C. Broceur. 
Universitats programm fiir 2 Sem. 1882. (Christiania: A. W. 
Brégger, 1882.) 
THE SILURIAN STAGES 2 AND 3 IN THE CHRISTIANIA DISTRICT, AND 
ON THE EKER; THEIR SrRucTURE, FossiILs, DISTURBED SLATE- 
ROCKS AND ConTACT-METAMORPHISM. By W. C. Broce. 
HE geologist, like other living beings, is affected by his environ- 
ment,—under unfavourable conditions, like those occurring in 
Holland, he is almost extinguished, and in other areas, there is a 
close connexion between the character of his work and the geological 
structure of his country. Our own island, with its numerous rock- 
systems, has given birth to men who have studied rocks of many 
ages, and originated bold generalizations, and at the same time, too 
often to men who are unwilling to spend very much of their time in 
observation of smaller details. The Scandinavian peninsula, on the 
other hand, possesses few rock-systems, and consequently the atten- 
-tion of its geologists has been greatly concentrated upon the Archzan 
and Lower Paleozoic rocks. This being so, it might be thought 
that little work would remain undone in that area, but the book 
before us very effectually banishes that idea. Professor Broégger, it 
is true, only describes a very small thickness of rock (less than 500 
feet), but he has devoted a great amount of labour to the study of 
this, and the result is a very complete account of the stratigraphy, 
paleontology, physical geology, and geognosy of the two stages. 
The stages themselves may be of small interest to many English 
geologists, but it is hardly an exaggeration to say that students of 
any branch of geology whatever, will find in this work new facts 
bearing upon their labours. Itis to be hoped that Professor Brégger’s 
removal from Christiania to Stockholm will not prevent him from 
issuing works on other stages. 
The author commences with an account of the subdivisions of 
stage 2 (the Olenus-schiefer), and stage 3 (the Asaphus-etage), 
giving a full description of their local development, variations in 
