THE KAMPA SYSTKM. ^3 
and Velatcs. The last-named genus occurs in considerable profusion 
in the upper part of the limestone, and extends into the overlying 
shaly foraminiferal limestone; at Tiina, however, it was found also 
in the lower beds with Nmitilus sp. cf, subLxvigatiis d'Orb. The 
commonest — possibly the only — species is Velates schmideliana 
Chemn.,^ which determines the age of the limestone as eocene. 
In addition to the above fossils, part of a claw of a crab was found 
at the top of the limestone on the ridge behind Tiina. 
The gastropod limestone is overlain by a shaly nodular limestone 
containing large numbers of foraminifera, chiefly 
Operculina limestoae. 
Operculina and other Nummulinidse. In the 
neighbourhood of Kampa dzong this rock is usually found capping the 
ridge to the north of the village, and it occupies a similar position on 
the ridge to the north-west of Tiina (see Plates 8, fig. l, and 12, fig. 2), 
When found in this position it usually resembles a nodular calcareous 
shale rather than a limestone, for, owing to its soft and shaly character, 
it readilv succumbs to the violent disintegrating- forces at work in the 
extreme climate of Tibet. In less exposed sections, however, it appears 
more compact, and in the Kampa gorge at about half a mile above 
the fort it forms steep cliffs bordering the stream (see PI. u, fig. 2). 
This rock forms a very characteristic and readily recognised 
horizon. It is always markedly nodular, and the nodules, being 
harder and more compact than the shaly interstitial matter, stand out 
conspicuously on the cliff face ; at the same time they appear to be 
covered with small dark specks which on closer inspection prove 
to be foraminifera weathered out from the soft matrix. Few fossils 
other than foraminifera occur in this limestone, but gastropods and 
lamellibranchs were found both at Kampa dzong and Tiina and 
Nautili at Tiina. The gastropods are represented chiefly by Velates 
schmideliana Chemn., which is fairly common in the highest beds 
of the limestone at Kampa dzong : at least two species of Nautilus 
occur, one of which closely resembles A'', sublaevigatus d'Orb. 
^ I am indebted to my colleague, Mr. G. H. Tipper, for the determination of 
this species and also for much assistance in dealing with the fossils from the 
underlying Cretaceous beds. 
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