144 
DIENER : TRIAS OF THE HIMALAYAS. 
It becomes clear from this table that the number of cephalopod- bear- 
ing horizons in the Himalayas is considerably larger in the Lower Trias 
than in the Alps, but smaller in the ladinic and noric stages. The ab- 
sence of cephalopod horizons in the alaunic and sevatic (middle and 
upper noric) substages of the Himalayas is easily explained by the 
different development of facies in the Indian and Alpine regions. In 
the Alps it is only in the Hallstatt facies of the Salzkammergut that 
cephalopod facies are known, not in the Liihothamnium and bivalve 
facies of the Dachsteinkalk. But in rocks of the Hallstatt facies, as 
they are known to us from the Tibetan facies in the Himalayas, only 
the carnic stage is represented. The expectation may, however, be 
indulged in that in the Tibetan region further investigations may lead 
to the discovery of exotic blocks with middle and upper noric faunae. 
The presence of a single cephalopod fauna in the ladinic stage of the 
Himalayas is more remarkable. In the Alps three faunae have been 
distinguished in this stage by E. v. Mojsisovics, two of them (Buchen- 
stein and Wengen) being quite distinct and restricted to two stratigra- 
phical horizons of wide distribution. In the Himalayas one fauna only 
corresponds to those three Mediterranean ones and this is the fauna of 
the Wengen beds with Pr Hmchijceras Archelaus and Daonella Lommeli. 
But there is certainly no break in the succession of beds, either in Spiti 
where the ladinic stage is at least 300 feet in thickness, or in Painkhanda 
where it is reduced to a thickness of 10 or 20 feet. In all the sections 
that have been examined by A. v. Krafft, true passage beds have been 
noticed connecting the upper Muschelkalk with the ladinic stage. From 
this we must infer that the topmost beds of the upper Muschelkalk, 
containing Ptychites Gerard! Blfd. and Joannites cf. proavus Dien., re- 
present also stratigraphical equivalents of the Alpine Buchenstein beds 
the existence of which cannot be proved on palseontological grounds. 
The following table shows a correlation of the Triassic cephalopod 
horizons of the Himalayas and of the Boreal and Pacific regions. Our 
limited knowledge of the Trias in the Arctic regions and in the south- 
ern part of the Pacific is a serious obstacle to any attempt of this 
kind :— 
( 345 ) 
