308 REVIEWS 



The physical characters of each of these formations is briefly 

 described, though no lists of fossils are given by which the faunas may 

 be compared with those of the supposed equivalent strata elsewhere. 



The remainder of the report will have its chief interest and useful- 

 ness among the local geologists of the region described. 



Stuart Weller. 



Fijial Report 071 tJie Geology of Minnesota. Pal(2o?itology . Vol. Ill, 

 Part II. Minneapolis, Minn., 1897. 



Part II of the PalcEontology of Minnesota, a volume of about 

 600 pages, illustrated by forty-eight plates besides 133 figures, has 

 just appeared. Like its companion volume, Part 1, it treats only of 

 the Ordovician fossils. Besides the introduction, which is a paper by 

 N. H. Winchell and E. O. Ulrich upon "The Lower Silurian deposits 

 of the Upper Mississippi province ; a correlation of the strata with 

 those in the Cincinnati, Tennessee, New York, and Canadian provinces, 

 and the stratigraphic and geographic distribution of the fossils," the 

 volume contains the following papers : 



1. The Lower Silurian Lamellibranchiata of Minnesota. By E. O. 

 Ulrich. 



2. The Lower Silurian Ostracoda of Minnesota. By E. O. Ulrich. 



3. The Lower Silurian Trilobites of Minnesota. By J. M. Clarke. 



4. The Lower Silurian Cephalopoda of Minnesota. By J. M. Clarke. 



5. The Lower Silurian Gastropoda of Minnesota. By E. O. Ulrich 

 and W. H. Scofield. 



The first three of these papers were published separately in small 

 editions and distributed during the period from June 16, 1894,10 Sep- 

 tember 27, 1894. The last two papers appear for the first time with 

 the publication of the complete volume. 



The volume supplies a long-felt want to students of the Ordovician 

 faunas of the West, and will doubtless be the standard work upon these 

 faunas in the Mississippi region for many years. The author of the chap- 

 ters upon the Lamellibranchiata and Gastropoda should perhaps have 

 been more conservative in establishing new genera and species; how- 

 ever the classification of the greater number of the classes of organisms 

 abundantly preserved as fossils in the palaeozoic rocks, is at present in 

 a transition state, and any attempt to make more natural, and to give 

 more definiteness to their classification is a step in advance. 



Stuart Weller. 



