Geology and Mineralogy . 85 



of Canada, in Great Britain, Belgium and France, such coasts 

 being known as Rias coasts) they have sunk into the depths. 

 Regarding the continental shelf being "so marked, obvious and 

 universal a feature of the earth's surface that it affords the 

 strongest kind of evidence of the antiquity of the ocean basins 

 and the limits beyond which the continents have not extended" 

 (308-309), the reveiwer holds that the present continental shelf 

 is of modern construction, certainly of late Cenozoic making, 

 and simply represents the land wash within the zone of wave and 

 tidal action. With every shrinkage of the earth and subsidence 

 of the oceanic areas the margins of the continents are locally or 

 regionally warped downward and new continental shelves are 

 developed upon the sunken areas. The possible increase in the 

 amount of water during geologic time is left out of consideration 

 (309) and nowhere is there a word as to why most of Africa and 

 eastern South America have broken-down coasts instead of 

 uplifted and folded margins. 



The reviewer heartily recommends the work to paleontologists 

 and zoogeographers, as the author is believed to he sound in his 

 general premises regarding the distribution of land animals 

 during Cenozoic time. Some years ago the reviewer under- 

 took a similar study, starting out with the theory that Africa 

 and South America were still united in early Tertiary, but grad- 

 ually came to the conclusion that these lands had been broken 

 through by the Atlantic in Lower Cretaceous (Upper Comanchian) 

 times. c. s. 



2. Publications of the United States Geological Survey, 

 George Otis Smith, Director. — Recent publications of the U. S. 

 Geological Survey are noted in the following list (continued from 

 vol. xxxix, pp. 316-318) : 



Topographic Atlas — Sixty-seven sheets. 



Professional Papers. — No. 88. Lavas of Hawaii and their 

 relations; by Whitman Cross. Pp. 97; 4 pis. See p. 88. 



No. 90. Shorter Contributions to General Geology. I. The 

 Stratigraphy of the Montana Group with special reference to the 

 position and age of the Judith River Formation; by C. F. 

 Bowen. Pp. 95-153; 1 pi. J. The Cretaceous-Eocene contact 

 in the Atlantic. and Gulf Coastal Plain; by Lloyd W. Stephenson. 

 Pp. 155-182; 9 pis., 8 figs. K. The History of a portion of 

 Yampa River, Colorado, and its possible bearing on that of Green 

 River; by E. T. Hancock. Pp. 183-189; 2 pis. L. The Inor- 

 ganic constituents of Echinoderms; by F. W. Clarke and W. C. 

 Wheeler. Pp. 190-199. 



No. 95-A. The composition of muds from Columbus Marsh, 

 Nevada; by W. B. Hicks. Pp. 11, 1 fig. 



Bulletins. — Nos. 559, 560, 563, 567. Results of Spirit Level- 

 ing. R. B. Marshall, Chief Geographer. No. 559. Michigan, 

 1911 and 1913. Pp. 79; 1 pi. No. 560. Minnesota, 1897-1914. 

 Pp. 190; 1 pi. No. 563. Maryland, 1896 to 1911, inclusive. Pp. 

 80; 1 pi. No. 567. Idaho, 1896-1914. Pp. 130; 1 pi. 



