THE HUMAN SPECIES. 31 



fill up, and the surf threw back in the form of sand 

 and gravel, until the whole space was filled, down to 

 the edge of deep water, where the currents generated 

 by the monsoons first had power to act ; then the pre- 

 sent delta, which began higher up, was finally checked 

 or reduced to very gradual additions. Nor is this sup- 

 position visionary. What the daily deposits can pro- 

 duce, in a course of ages, may be inferred from Dr, 

 Lord's calculation ; for he, assuming the discharge of 

 the river to be three hundred cubic feet of mud per 

 second, maintains it, as equal to form in seven months, 

 an island forty-two miles in length by twenty-seven in 

 breadth, and forty feet in depth ; which, though the re- 

 maining five months may not continue an equal daily 

 deposit brought down from high Asia, even with th$ 

 allowance, that a considerable exaggeration may exist 

 in the estimated quantities, is, nevertheless, sufficient 

 to have replenished a gulf of shoal water, of enormous 

 extent, in a few centuries. Proportionably as the cur- 

 rent shifted to the westward, the monsoon winds filled 

 up the abandoned beds of the stream with drift sand, 

 leaving only those of former affluents to continue their 

 course, and the plain to become a desert of sand, formed 

 in ridges, sometimes of considerable height; for the 

 coasts of France, Holland, and of the Baltic near 

 Dantzig, demonstrate, that the surf and winds can 

 elevate them to more than eighty feet, without a single 

 ingredient in their mass to give them real stability. 

 Such is the desert of the Indus from above the junction 

 of the Sutlege (Hyphasis), the lowest of the Punjaub 



