KAMET AND SPiTI. 219 



The shales also yielded many specimens of Producti and a few other 

 Brachiopods. 



These shales are evidently Stoliczka's typical Ruling beds. They 

 are well exposed near Tilling, Khar and Ruling, and may easily be 

 traced as a black band near the base of the hills north of Ruling. 

 They again are visible in the Spiti river valley west of Dangkhar, 

 below the wooden bridge above the junction with the Pin river. 

 They yielded fossils wherever met, and are invariably passing upwards 



into beds, which Stoliczka failed to distinguish. 



These are dark limestone beds alternating with 

 black friable shales, of about 200 feet in thickness and closely resem- 

 bling the Productus shales below. But these beds have yielded, in 

 all sections which I have hitherto examined, a fauna totally distinct 

 from that found in the beds below\ Numerous species of Cephalo- 

 pods, chiefly of Xenodiscus, Otoceras, and a little higher up of Cera- 



tites, may be picked up. Producti have dis- 

 Lowest trias horizon. , . . . . , c A , 



appeared, and in the uppermost beds 01 the 

 series Brachiopods are found which I cannot distinguish from species 

 found in the lowest trias of the Alps. 



This succession of beds is well seen near Ruling, north-west of 



the village, where it is conformably overlaid by 



IVf us cli 6 1 k<il Ic 



limestone with Muschelkalk species, followed by 



the remaining trias horizons. 



The beds with Otoceras tvoodwardi form a true passage-bed from 



the permian Productus shales into the lowest 

 Otoceras stage (pas- r 



sage-beds). trias. Its exact homotaxis can now be estab- 



lished, for beds containing a fauna nearly related to the Himalayan 

 one have been found in both Western Asia (Araxes) and in Sicily 

 within the last few years. The fact of the disappearance of the 

 Producti, and of the general habitus of the Cephalopod fauna remind- 

 ing one of triassic horizons, have determined me to class the Oto- 

 ceras zone — a passage stage — with the trias, while it may be probably 

 correlated with the lowest formations of the Bunter ; but there is 

 really no sharply-defined boundary, no stratigraphical distinction 



( 219 ) 



