686 REVIEWS 



ture makes it therefore a very unsatisfactory horizon term when used 

 alone. 



The section on the morphology, classification, and occurrence of 

 Palaeozoic ostracods, which is the work of the two foremost authorities ^ 

 in America on this group — Dr. Ulrich and Dr. Bassler — will be indis- 

 pensable to all students of these fossils. It includes in addition to all 

 that the title suggests an excellent discussion of methods of study. 

 This extremely valuable contribution should go far toward encouraging 

 students to take up the study of this somewhat neglected group of fossils. 



The Maryland Survey deserves the thanks of all palaeontologists 



for the admirable style in which this much-needed volume has been 



published. 



E. M. Kindle 



North American Later Tertiary and Quaternary Bryozoa. By 



Ferdinand Canu and Ray S. Bassler. United States 



National Museum, Bulletin 125, Washington, 1923. Pp. 



i-vii+ 1-302, pis. I-XLVII, 37 figures in text. 



This volume forms the concluding part of studies by the same authors 



on the Tertiary and Quaternary Bryozoa of North America. Like 



its predecessor^ this one conforms to the high standard of scientific 



research established in this group of organisms. The Bryozoa are now 



in a position to be used by the geologist and stratigrapher as a valuable 



aid in the tracing and identification of marine sediments. If other groups 



of animals had been as thoroughly described and excellently pictured as 



this, many problems would be much easier of solution. 



The major portion of the book consists of descriptions of Miocene 

 and later fossil Bryozoa arranged according to the scheme of classification 

 previously adopted. A catalogue of all papers dealing with the subject 

 from 1841 (the first) to date is given with a synopsis of the contents. 

 Also a bibliography of the literature of the Bryozoa, living and fossil, 

 is given for the years 1899 to 1923. Literature prior to 1900 is contained 

 in a previous publication.^ The plates are made from a large number 

 of individual photographs of striking beauty and clearness. The excel- 

 lence of these pictures deserves warm commendation because they will 

 be used probably more than any other part of the book, and because 



* North American Early Tertiary Bryozoa, United States Nat. Mus. Bull. 106, 2 

 vols., 879 pp., 162 pis. 



* Nickles and Bassler, United States Geological Survey, Bulletin 173. 



