592 THE JOURNAL OF GEOLOGY. 
liminary to the descriptions of fossils which make up the remaining 
six chapters of the volume and the six chapters of the succeeding 
volume. 
The grouping of the descriptions of fossils is biological, the chap- 
ters embracing Protozoans and Sponges (IV.), Hydrozoids and Corals 
(V.), Echinoids and Asterids (VI.), Cystids and Blastoids (VIL), 
Crinoids (VIII.), Worms and Crustaceans (IX.). These are in the main 
re-descriptions of species already known, the justification of this 
appearing in the author’s introduction, in which the inaccessibility of 
the larger part of the original descriptions and the imperfection of 
some of them is urged. Twenty-one lithographic plates are given to 
illustrate the fossils described. An appendix containing a stratigraphic 
catalogue of Missouri fossils and a geological map of the state are 
added. 
Volume V. is practically a continuation of Volume IV. and embraces 
six chapters relating to polyzoans, brachiopods, lamellibranchs, gastero- 
pods, cephalopods and vertebrates. These are followed by an indexed 
list of the fossils of Missouri. ‘Twenty-four illustrative plates accom- 
pany this volume. 
Volumes VI. and VII. relate to the lead and zinc deposits, and are 
the work of ex-Director Winslow. As in the palzeontological part, the 
separation into two volumes is merely a matter of mechanical convent- 
ence, the contents being closely consecutive. The subject is opened 
with a historical sketch of lead and zinc mining. The treatment is 
brief, but covers a wide range in time and geographic distribution. 
The nature of the metals is then discussed, followed by a chapter 
devoted to their distribution. Emphasis is laid upon the distinction 
between the diffused and the concentrated conditions, a distinction 
which is wholly determinative of their economic value, and scarcely 
less important in the study of their genesis. The ore deposits are 
classified successively on the basis of their composition, the mode of 
formation of the constituents, their sources, the forms of the ore body, 
the attitudes of the ore body, their structures, the natures of the associ- 
ated substances, the natures of the calcareous rocks, and their geologi- 
cal position. Asynoptical description of the lead and zinc deposits of 
foreign countries and of states other than Missouri occupies two chap- 
ters, and gives evidence of good judgment in the selection of the more 
important data. This is followed by a chapter prepared by James D. 
Robertson on the metallurgy of the metals, illustrated with cuts of 
