niENER : TRIAS OB THE HIMALAYAS. 
In a special paper treating with the problem of the age of the Olenek 
beds 1 I have tried to refute Noetling's arguments. The Indian and 
Siberian species of Keyserlingites {Ceratiies subrobusti) are not identical 
and do not even belong to the same group of forms. In the Himalayas 
the genus Ceratites is not restricted to the Muschelkalk, but is 
represented in the Hedenstroemia beds by typical species of the group 
of circumplicati {Hollandites). There are some affinities between the 
Olenek fauna and the Hedenstroemia stage, but none at all with the 
Himalayan Muschelkalk. Hedenstroemia Mojsisooicsi Dien. is either 
identical or very closely allied to the Siberian species, which has been 
described as Meekoceras sp. ind. aff. Hedenstroemia by E. v. Mojsisovics, 
There are also strong affinities between some Indian and Siberian 
representatives of the genera Meekoceras and Xenodiscus, as has been 
suggested by Freeh, especially between Xenodissus rotula Waag. and 
X. hyperborosiis Mojs. But the most important argument in favour 
of a correlation with the Hedenstroemia beds is the occurrence of 
Xenodiscus, Meekoceras, Aspidites, Hedenstroemia and Prosphinngites in 
the Olenek fauna, all genera, which in the Himalayas are restricted to 
the Lower Trias and do not range into the Muschelkalk. 
The faunistic affinities of the Olenek beds with the Columbites beds 
of North America, as advocated by J. P. Smith, is in accordance with 
this correlation. 
On the other hand NoetHng is certainly right in assuming that the 
connection of the Indo-Chinese and Northern Siberian provinces has 
not been a very close one. The peculiar character of the Olenek fauna? 
especially the enormous preponderance of Dinarites spiniplicati 
(Olenekites Hyatt), is indicative of a comparative isolation of this basin 
of the Triassic Arctic sea. 
The Permo-Triassic boundary. 
The determination of the upper limit of the Permian rocks in the 
marine series of India did not trouble the students of the geological 
formations in the Himalayas until it had been suggested by Noetling's 
studies in the Salt Range. 
1 C. Diener : Das Alter der Olenekschichten Sibiriens. Centralblatt. /. Min.> 
etc., 1908, p. 2.33. 
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