1919.] History of the Drainage of Northern India. 85 
down over a wide extent of country and accumulated toa 
colossal thickness in Jammu and Kangra between the Chenab 
and the Beas rivers. Going westward it thins out re but 
is again developed to some extent north of the Sa lt Range, 
again dies out southward but repeats itself in Pistiees and 
Bhutan. On the accompanyin map, Plate II, Fig. 2, repre- 
approximate position of the Upper Siwalik zone is indicated by 
a continuous thick line, while the dotted area marks the occur- 
diminishes to that of an orange. Smaller pebbles than this are 
not frequent, though there is a certain amount of sand and clay 
which helps to bind the whule together. As a general rule they 
are well rounded. 
The greater number of the boulders are of quartzite but 
quite a number of slate and vein quartz occur and locally we 
find them composed of granite, trap rock, limestone, as well as 
of the Lower Siwalik sandstone. 
The age of the uppermost beds of the Siwalik series are 
dated with a fair amount of accuracy by the first occurrence 
in them of Camelus, probably a migrant from Central Asia. In 
North America the earliest beds in which this genus has been 
found have been referred to the lowest Pleistocene. The writer! 
has placed the whole Siwalik series into the Pliocene, in which 
case the Camelus beds of North America should perhaps be 
slightly antedated. He is now inclined to think, however, 
that the topmost beds of the Siwaliks are nee ya hte aati 
pressed by Lydekker? thirty years ago. 
It is ‘generally agreed that no portion of the Siwalik series 
was contemporaneous with the so-called older alluvium of 
the Narbada, Godavari and Ganges, and, so Sk ng as an 
uneonformability between these two sets of beds 
seems a matter of little moment whether we Cinder that 
ie Siwalik era — with the Pliocene, or was continued 
into the Pleistocen 
The formation or a boulder bed of the kind that has been 
described may be due to various causes. 
| G. E, Pilgrim, Correlation of the Siwaliks _ on horizons of 
Europe. Rec. Geol. Surv., India, XLIII eos p. 3 
2R. bp tener § Indian Tertia tbe and P. i ghcpial vertebrate fauna. 
Pal. 
