The permo-teiassic boundary. 
43 
By C. L. Griesbach the base of the Himalayan Trias had been 
assumed to lie at the top of the Permian Productus, or Ruling, shales, 
which in all normal sections of Spiti and Painkhanda are overlain 
conformably by a series of dark thin-bedded shales and limestones, 
which have yielded the fauna of the Otoceras beds. 
Griesbach himself determined the Otoceras beds as Triassic at the 
time of their discovery (1879). In his memoir on the geology of the 
Central Himalayas (1891, p. 71) he looked upon them as a true passage 
bed between the Permian and Triassic systems, " as a horizon still lower 
than the Werfen beds of the Alps, and considerably lower than what 
is understood now as Bunter," but nevertheless decided to include 
them with the Lower Trias (1. c, pp. 121, 146, 174, 175, 177, 219). 
Waageni correlated the Himalayan Otoceras stage with the 
Otoceras beds of Julfa in Armenia and consequently included it in the 
Upper Permian, although he considered it to be younger than the Jabi 
or Cephalopod beds of the Upper Productus Limestone, " because the 
mesozoic types seemed to predominate over the palaeozoic ones " 
(1. c, p. 232). 
The correlation with the Permian Otoceras beds of Julfa was refuted 
by E. V. Mojsisovics,^ because the species of Otoceras in the last 
mentioned deposits occupy a remarkably lower stage of development 
than the Indian ones. The Otoceras stage of the Himalayas was 
therefore regarded as the oldest cephalopod-bearing horizon of the 
Lower Trias in India. In a subsequent paper Waagen ' acknowledged 
the Triassic character of the Otoceras fauna and defined the age of the 
beds including it as Lower Triassic. 
In 1897 C. Diener,^ after his examination of the fossil materials 
collected by Griesbach and by the expedition of 1892, supported the 
view given by E. v. Mojsisovics, by new evidence, enumerating the 
remarkable differences between the Otoceras faunae of Julfa and of the 
1 VV. Waagen : Salt Range Fossils, Palosont. Ind., ser. XIII, Vol. IV, Geologi- 
cal Results, p. 225. 
3 E. V. Mojsisovics : Voilaeufige Bemerkungen ueber die Cephalopodenfaunen 
der Himalaya-Trias. Sitzgsber. kais. Akad. d. Wissensch. Wien, 1892, CI, pp. 
372-378. 
s E. V. Mojsisovics, W. Waagen, C. Diener : Entwurf einer Gliederung der pelag- 
ischen Sedimente des Triassystems, ibidem, CIV, 1895, p. 1286. 
* C. Diener : Himalayan Fossils, Palceont. hid., ser. XV, Vol. II, Pt. 1. 
( ?-4i ) 
