REVIEWS 259 



brief general treatise. The fairly extensive bibliography of Mexican 



geology will be of value to many. 



A. H. B. 



Nomenclature and Description of the Geological Formations of Indi- 

 ana. By E. R. Cumings. Part IV, Handbook of Indiana 

 Geology. Publication 21, The Department of Conservation, 

 State of Indiana, 1922. 



This report is one of the six papers brought together in Professor 

 Logan's admirable handbook of Indiana Geology. Professor Cumings' 

 reputation as a stratigraphic paleontologist will lead the experienced 

 geological reader to expect a thorough piece of work in this section and 

 he will not be disappointed. The bibliography dealing with the stratig- 

 raphy and fossils of the state, which is an important feature of the work, 

 occupies thirty-six pages. Professor Cumings' intimate knowledge of 

 the fossil faunas of Indiana has enabled him to carry out the formidable 

 task of critically reviewing and summarizing the most pertinent data in 

 the several hundred papers represented in this extensive hterature in an 

 admirable manner. His detailed tracing of the history of each of the 

 fifty-eight formation names establishes a sound basis for a stable nomen- 

 clature. This careful review of the Indiana formational nomenclature 

 will be of much value to the geologists of adjacent states as well as to 

 those of Indiana. Geologists concerned with the nomenclature of geologic 

 formations may be interested in Professor Cumings' proposal regarding 

 the substitution of Medinan for Oswegan. Professor Cumings draws the 

 Ordovician-Silurian boundary at the top at the Richmond instead of at 

 the bottom, where some paleontologists have proposed placing it in 

 recent years. 



The well-planned geologic time scale summarizes, so^far as this is 

 possible on a single sheet, the present state of knowledge of the stratig- 

 raphy of the state. This important illustration should have had a 

 general title printed on it. 



A map showing type localities of geological formations in the Central 

 States and Southern Ontario is a useful feature of the report. It indi- 

 cates, however, only a small portion of the type localities in this extensive 

 region. A series of geologic sections across Indiana and eight paleogeo- 

 graphic maps illustrate the broader geological features of the state and 

 its past geological history, as interpreted by the author. 



The historical and bibliographic features of this paper will make it 

 an indispensable work of reference for stratigraphic paleontologists. 



E. M. Kindle 



