Reviews 



The Stratigraphy of the Western American Trias. By J. P. Smith. 

 Sonderabdruck aus der Festschrift zum siebzigsten Geburtstage 

 von Adolph v. Koenen gewidm. v, seinen Schiilern. Stuttgart: 

 E. Schweizerbartsche Verlagsbuchhandlung, 1907. 

 Since Lower Triassic times, and perhaps earher, the marine faunas 

 of western America have shown a close relationship with those of eastern 

 Asia, except when modified by the periodical invasions of Boreal forms 

 and the occasional interruptions of Mediterranean types which gained 

 access through Atlantic waters. At the present time the living marine 

 faunas of Japan and our Pacific coast show a large number of identical 

 species, though the intermingling of the shallow-water forms is prohibited 

 by deep water east of Kamchatka and by the cold current from Bering Sea. 

 A rise of 200 meters would close Bering strait and shut off the cold water 

 from the north, while a greater elevation would allow easy communication 

 between the shore forms of Kamchatka and the Aleutian Islands. It is 

 probable that the recurrence of comparatively small elevations and sub- 

 sidences of the North Pacific border accounts for the similarity of the faunas 

 of the eastern Asiatic and the western American coasts during some stages 

 and the invasions of Boreal types during others. This hypothesis assumes 

 that a uniform temperature did not necessarily exist over the entire earth 

 previous to the Tertiary, and it aims to show that the intervention of a Pacific 

 continent during Mesozoic time is unnecessary for the explanation of the 

 similarity of Asiatic and American faunas. An analysis of the Triassic 

 formations of western America and a summary of later stratigraphy forms 

 the basis for these conclusions. H. H. 



The Green Schists and Associated Granites and Porphyries of Rhode 

 Island. By Benjamin K. Emerson and Joseph H. Perry. 

 U. S. Geological Survey, Bulletin No. 311; 71 pp., map. Wash- 

 ington, 1907. 



This paper deals principally with the interesting Cambrian remnants 

 which occur in Rhode Island as broad isolated patches, and with the sur- 

 rounding eruptives. Special emphasis is placed on the remarkable series 



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