Reviews — C. D. WalcoU's Cambrian Brachiojpoda. 313 



of PalaBozoic rocks, but all palseontologists and all evolutionists 

 owe to the gifted author, Dr. Walcott, their cordial thanks for 

 a monograph dealing so fully with the Brachiopod fauna which 

 existed in those far-off days when the earth was yet in her youth. 



Looking at these two fine volumes, with their testimony to 

 careful scientific work on every page — these two volumes published 

 by the United States Geological Survey, well printed and 

 magnificently illustrated — one is doubtful whom to envy most, 

 the scientific investigator who has not only the ability and the 

 patience but also the time to execute such a task, or the Government 

 which so ably places his results before the world. Eor publication 

 is a very important factor. There is nothing more stimulating to 

 any worker than to know that his task when accomplished will be 

 adequately printed; there is nothing which undermines the workei-'s 

 energy more than a doubt whether his work may ever see the light/ 

 while the feeling that it may in the end be mutilated or very 

 inadequately presented on the score of expense is almost as fatal. 

 Scientific workers in other countries, then, might be forgiven if 

 they exclaim to Dr. Walcott, or to his Government, " Almost thou 

 persuadest us to become Americans! " 



What, however, of the contents of these volumes ? To criticize 

 them in detail would be futile. Dr. Walcott has made a life study 

 of the faunas of the Cambrian rocks, and his expert knowledge is of 

 worldwide reputation, proved and attested by many previous com- 

 munications. The present monograph on the Cambrian Brachiopods 

 of the world has occupied the author for the last ten years : that 

 it has been accomplished in that space of time is a tribute to the 

 author's untiring perseverance. 



"This monograph includes the description of 44 genera, 15 sub- 

 genera, 477 species, and 59 varieties of Cambrian Brachiopoda, and 

 of 3 genera, 1 subgenus, 42 species, and 1 variety of Ordovician 

 Brachiopoda. ... In this paper the Brachiopoda are treated in 

 three ways — historically, geologically, and zoologically. Historically 

 the treatment comprises (1) a bibliography and (2) a table of 

 synonymic reference. . . . Geologically the distribution of the 

 Brachiopoda is considered under the following headinjrs : (1) General 

 geographic and stratigraphic distribution; (2) detailed geographic 

 distribution; (3) detailed stratigraphic distribution; (4) habitat; 

 and (5) fossil localities. Zoologically the discussion covers (l)the 

 physical characters of the Brachiopoda ; (2) their distribution ; 

 (3) their evolution ; and (4) their classification. Lastly come the 

 detailed descriptions of genera and species and the illustrative 

 plates" (p. 11). 



The number of species of Cambrian Brachiopoda is remarkable ; 

 it is an interesting picture of how much development and differentia- 

 tion had been accomplished even in those early days. Tables of 

 Detailed Geographic Distribution are given in pp. 114 et seqq., but 

 one misses a comparative analytical table of numbers of species in 

 different regions. North America supplies by far the largest number 

 — the species are some hundreds ; but as a remarkable contrast South 

 America is credited with only five species. Next to North America 



