Geol.— Vol. I.] SMITH— COMPARATIVE STRATIGRAPHY. 337 



Oriental region with the eastern Siberian province of the 

 Arctic-Pacific region, and the American region. This is 

 shown by the community of species between the Asiatic 

 provinces, and the close relationships of many forms on 

 opposite sides of the Pacific Ocean. But the American 

 region has many genera that occur in one or the other of 

 the Asiatic regions, but are not known in both. Psetidosa- 

 geceras and Ussuria are not uncommon in the Meekoceras 

 beds of California and Idaho, and are known elsewhere 

 only in the Proptychites beds of Ussuri Bay. Lecanites 

 and Flemingites are common to the American and the 

 Oriental regions, but are unknown in the Arctic-Pacific. 

 Thus during Brahmanic time the two regions in Asia seem to 

 have not been directly connected, but rather to have mingled 

 their faunas through some outside sea, with which the 

 American waters were also connected. 



In Jakutic time the connection between northern and 

 southern Asia became more intimate, and we find two species 

 identical in the two regions, Ceratites subrobustus and Heden- 

 stroemia mojsisovicsi, and many others closely related. And 

 during this expansion of the Asiatic waters two Mediterrean 

 species, Meekoceras ? cafrilente, and Aspidites eiirasiaticiis 

 made their way into central Asia, although the occurrence 

 of a few doubtful species in the two regions can not offset 

 the fact that the most characteristic genera of the two are 

 wholly different.^ The faunas of the Scythic series have 

 been described by the following writers : Arctic-Pacific 

 region, E. von Mojsisovics (20 and 25) and Carl Diener 

 (5); in the Oriental region, by W. Waagen (38) from the 

 Salt Range, and from the Himalayas by Carl Diener (3) ; in 

 the American region, from the Aspen Mountains of Idaho by 

 C. A. White (40), and from the Inyo Range of California 

 by J. P. Smith (33). 



The Scythic faunas of the Mediterranean region are de- 

 scribed by E. von Mojsisovics in his monograph, " Die 

 Cephalopoden der Mediterranen Triasprovinz " (21). 



iDr. A. von Kraflft, " Stratigraphic Notes on the Mesozoic Rocks of Spiti " (1900), says 

 that Ceratites subrobustus does not occur in the Himalayas in the beds called by Dr. Diener 

 "The Subrobustus beds," but in the next higher group, " Sibirites prahlada beds," so- 

 called base of the Muschelkalk. 



