COKRELATION OF THE LOWER TRIAS. 
41 
The evidence furnished by a comparison of the lamellibranchs 
must be considered as very important, justifying a direct correlation 
with the Alpine Seis beds, with which the fauna of Vladivostok has 
not less than twelve species in common.' 
Ammonites of Lower Triassic age, which can, however, not be as- 
signed to a definite stratigraphical horizon, have been quoted from 
Yunnan by Douville, and from the Semenow Range (N. E. Tibet) by 
Schellwien. 
Less close than the relations of the Indian Meekoceras beds with 
the fauna of Vladivostok are those of the Hedenstroemia stage with 
the Olenek beds of Northern Siberia. The richest Triassic fauna from 
Siberia hitherto known has been collected from a concretionary lime- 
stone imbedded in dark shales, at the mouth of the Olenek river. Not 
less than forty species of Cephalopoda have been described by E. v. 
Mojsisovics.'- Nevertheless the age of the fauna has been a subject of 
controversy. 
E. V. Mojsisovics considered the Olenek beds as the homotaxial equi- 
valent of the Campil beds, although no identical or even nearly allied 
species were known to him from both regions and this correlation was 
only based on the general zoological character of the Olenek fauna. 
A considerably younger age was assigned to the latter by Noetling.^ 
His opinion is supported by the three following arguments : — 
(1) Ceratites {Ket/serlingites) subrobustus Mojs. has its habitat in the zone 
of Spiriferina Stracheyi of the Himalayan Muschelkalk ; (2) in India 
the genus Ceratites, which in the Olenek fauna is represented by 
several groups, does not make its appearance before the commencement 
of the Muschelkalk ; (3) the difterences between the faunae of the Indian 
Lower Trias and of the Olenek beds are sufficiently remarkable to exclude 
their homotaxis. 
1 A. Bittner : Versteinerungen aus den Triasablagerungen des Sued-Ussuri- 
gebietes, etc., ibidem. Vol. VII, No. 4, 1899. P. v. Wittenburg : Neue Beitraege 
zur Geol. und Palaeont. d. Werfener 8cliicliten Suedtiiols mit Berueckvsichtigung 
der Schichten von Wladiwostok. Ceniralhl. f. Min., 1908, p. 67. Notiz ueber 
Trias und Jura bei Wladiwostok. Neues. Jahrb. /. Min., 1909, Bd. I, p. 1. 
2 E. V. Mojsisovics : Arktische Triasfaunen, Mem. Acad, imper. des sciences, 
St. Petershourg, 1886, VII. Ser., Vol. XXXIII. Ueber einige arktische Triasam- 
moniten des. noerdl. Sibuien. ibidem, 1888, Vol. XXXVI, No. 5. 
F. Noctling : Asiatiache Trias, Lelhwu ?nesozoica, I, p. 200. 
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