46 HAYDEN : GEOLOGY OF THE PROVINCES OF TSANG AND 0. 
In addition to these a species of Lithodomus, apparently identical 
with L. {Modiola) deshayesii Dixon, from the calcaire grossier of 
the Paris basin, occurs in considerable quantity in the Lithothamnion 
limestone. The species of Plicatiila occur in the reddish arenaceous 
limestone and Cyclolites regularis together with Caprina sp. and 
other lamellibranchs in the overlying band. The former genus was 
found wherever a section of the uppermost Cretaceous rocks was 
examined ; it is particularly common in the locality, shown on PI. g, 
which lies at about seven miles to E.S.E. of Kampa dzong. 
The overlying sandstone and grey limestone, which intervene 
between the coral limestone and ferruginous sandstone are poor 
in fossils; the few which were found in the grey limestone consist of 
echinoids and traces of brachiopods, none of which were even 
generically determinable. 
The whole of the above series from the Hemiaster shales to 
the ferruginous sandstone is seen throughout the Kampa-Tatsang 
ridge and again in the hills to the W.N.W. of Tuna, but at the 
latter village only the uppermost beds are exposed. In the imme- 
diate neighbourhood of Kampa dzong the beds overlying the 
third limestone are frequently hidden by talus derived from the 
ferruginous sandstone, and they were examined in greater detail at 
Tiina, where, however, the fossils are unfortunately in a very poor state 
of preservation. 
To the north and north-west of Tuna, Cretaceous and Tertiary 
beds extend for probably ten or twelve miles, but unfortunately 
no detailed examination could be made of that area. A reconnais- 
sance to the valley of the Guru river, at some miles above Guru, 
showed, however, that good sections were to be found in the hills to 
the west of that village. In the range to the south of the river the 
limestones with Rudistse are well exposed and contain many fossils, 
while the higher peaks to the north of the river appeared to afford 
sections of both the Cretaceous and Tertiary systems, of which the 
latter may very possibly include beds younger than any found either 
at Tiina or at Kampa dzong. 
( 167 ) 
