16 BOMBAY NATURAL HISTORY SOCIETY. 
My readers will have noticed that it contains one cetacean, one 
erocodilian, and one fish, which do not occur elsewhere in waters 
flowing into the Arabian Sea, but abound in those that meet the 
Bay of Bengal. These are Platanista gangeticus, Gavialis gan- 
geticus and Labeo rohita. 
The cetacean, like all other cetaceans, cannot landat all. The 
reptile is the most aquatic of all the crocodilia, and its movement 
ashore is confined to crawling on toa sand bank fora nap. The 
fish (a thing necessary to specify in India, where we have several 
fishes quite at home out of water), is a high Cyprinoid, and incap- 
able of terrestrial movement. How did they get there? 
The answer is in one of the strangest chapters of recent geology, 
known to Indian professors of that art as the “ Legend of the Lost 
River.’’ 
Many of my readers know that the great and ancient rock 
formations of the Peninsular proper are separated from the loftier 
but more modern Himalayas, and Afghan and Belooch hills, by a 
great elbow-shaped plain, the west part of which forms the valley of 
the Indus and great Indian Desert ; while the Hastern is the region 
of the Ganges and its tributaries. The former is mostly sand, 
and the latter mostly loam, but they melt into each other between 
the Jamna and the Satlej at an almost imperceptible watershed, 
nearly due south of the famous Siwalik Hills, and pretty well 
identified with the legendary land of Kurukshetra, the cockpit of all 
decisive Indian wars, from the time of the Mahabharat until a new 
element of battle arose out of the sea. ; 
Here, all Indian legends say, flowed a sacred stream, the Saras- 
wati, which joined the Jamna, and is still supposed, by a pious 
fiction, to do so at Prayaga or Allahabad. In that region the 
Saraswati is not now recognizable to the modern geographer. But 
about the doubtful watershed there are certain ancient channels 
that fill in time of great rain. And by the help of these, and of our 
modern knowledge of the laws that govern rivers, we can piece out 
the story of the Lost River. 
It probably did originally join the Jamna, and drain into the 
Bay of Bengal. But being a river of the Northern Hemisphere, 
flowing at an angle to the Equator, it was bound (by laws which 
need not here be discussed in detail) to bear upon its right, or 
western bank, and probably did so until, in some year of mighty 
floods, it cut through the contemptible watershed, and turned ‘its 
