Geology. 397 



the great Roman Empire fell, what was the cause of the Dark 

 Ages, and why the diabolical government of modern Turkey 

 exists. A favorable climate produces the greatest number of 

 healthy beings, and an unfavorable one, a nation of laggards, 

 more or less sick and helpless. c. s. 



3. Brachiopoda of the Australasian Antarctic Expedition, 

 1911-1914; by J. Allan Thomson. Scientific Reports of the 

 Expedition, Ser. C. — Zoology and Botany, vol. 4, pt. 3, 76 pp., 

 4 pis., 1 map, 1918. — To state that this excellent work on recent 

 brachiopods treats of the new genera Amphithyris, Gyrothyris, 

 and Stethothyris, and of fifteen species of which nine are new, 

 is only to mention the groundwork that leads to biologic and 

 paleogeographic generalizations of a wide scope. The living 

 material described here from the Antarctic coast-line, Macquarie 

 Islands, and Tasmania, is also considered in the light of the Ter- 

 tiary brachiopods of the southern hemisphere. The author 

 furthermore points out that in all probability the family Tere- 

 bratellidae will have to be again subdivided. 



As the larvae of most brachiopods (all Articulata) are without 

 a mouth and must settle to the sea-bottom in probably not more 

 than twelve days if they are to feed and live, their development 

 prevents the young from crossing from one continent to another. 

 Therefore cases of discontinuous distribution appear to have a 

 profound significance and help to decipher former shallow-water 

 areas or lands that are now either completely sunken into the 

 deeps, or to indicate lands that are now more or less fragmented. 

 In this way, Blochmann and Schuchert have shown, on the basis 

 of living brachiopod distribution, the former presence of ancient 

 Gondwana. 



The reviewer in 1911 thought that the habitats and the bathy- 

 metric and geographic range of living brachiopods were fairly 

 well established for all regions north of the equator, but that a 

 great deal more would be learned about those of the Antarctic 

 seas. It now seems that he did not fully realize the many new 

 facts that would so soon come to light about the austral repre- 

 sentatives. Thomson points out that these southern oceans have 

 long been generating centers for peculiar genera and species, 

 and that not only did boreal forms pass into the southern hemis- 

 phere, but that even " northern forms originated in the south. 

 Yet the southern Tertiary faunas were at least as rich and 

 varied as those of the north." The author is hopeful that 

 "When all the Recent and Tertiary species of the southern 

 hemisphere have been correctly placed genetically, it may be 

 possible by the aid of brachiopods alone to gain a fairly accurate 

 idea of the latest former land connections of the southern hemis- 

 phere" (53). 



The paper under review is accompanied by a very valuable 

 new bathymetric map of the Antarctic and Southern oceans, 

 which includes all of the latest soundings and in which the shad- 



