96 REVIEWS 



island masses in northern South America and central Africa, and the 

 great boreal continent connecting North America with Eurasia. The 

 austral faunas flourished on the northern strand of the austral continent, 

 separated from the northern facies by the broad central ocean. The 

 two types seem to have sprung from the same Silurian ancestors, to have 

 diverged slightly in isolation under the influence of their environment, 

 but to have developed along similar lines on account of "long-standing 

 impulses in definite development which realize themselves notwith- 

 standing conditions of geographic isolation." It would seem that we 

 have here one of the most remarkable and definite cases of orthogenesis 

 in the world's history. 



There are in the fauna thirteen species of Trilobites of the genera 

 Homalonatus, Cryphaeus, Calmonia, Proboloides, Pennaia, rarely agree- 

 ing fully with their boreal kindred, but usually differing subgenerically, 

 at least. The Cephalopoda are represented by only two species, Ortho- 

 ceras and Kionoceras. Conularia is abundant, and the Pteropods have 

 one genus Hyolithus. Gastropods are not abundant, having only six 

 species. The Pelecypods are abundantly represented by twenty-four 

 species of Palaeoneilo, Nuculites, Nuculana, Janeia, Leptodomus, Modio- 

 morpha, Sphenotus, Pholadella, etc. The complete absence of the Aviculids 

 and Pterineids shows a sharp contrast with the northern Devonian faunas, 

 as does also the overwhelming development of the Taxodonts (Arcacea) 

 in both numbers and size. The Brachiopods are numerous with twenty- 

 four species of which the most noteworthy are Spirifer jheringi, S. 

 antarcticus, S. kayserianus, and the numerous Schuchertella, Leptostrophia, 

 Chonetes, and Discinacea. There are two starfishes and two sponges. 

 Corals are almost entirely lacking, and Bryozoons completely so. 



The volume is illustrated by twenty-seven beautiful lithographed 

 quarto plates of fossils done in the best style of Werner and Winter of 

 Frankfort, that make the best of half-tones look tawdry in comparison. 

 There are also several excellent text-figures. 



Brazil may well be proud of the first volume of the monographs of 

 its geological survey, for it has set an unusually high standard in subject- 

 matter and in mechanical execution. 



James Perrin Smith 



Leland Stanford Junior University 



