142 F. A. de Roepstorff, — On tlie Inliabitants of the Nicolars. [ Jtjlt, 



inollusk Potamides (Pirenella) Layardi, H. Ad., was found living. This 

 species is common in backwaters and salt lagoons on the Indian coast, and 

 proves that the salt lakes in which it now lives were once in communica- 

 tion with the sea. It is probable that in geologically recent times a great 

 inlet ran from what is now the Rann of Kachh up the Indus valley for a 

 distance of certainly more than 100 miles, and probably much further. 

 The occurrence of great quantities of salt in the Liini valley south-west of 

 Jodhptir, and the low elevation of the region point to the probability of 

 another arm of the sea having extended in that direction, whilst it is possible 

 that either from the south or north-west an inlet may have extended to the 

 Sambhar Lake. 



It is further shewn that the great accumulation of sand in two tracts, 

 one along the edge of the Indus alluvium, the other in a belt running north- 

 ward from the lower Luni valley, also favoured the idea of former inlets of 

 the sea in those directions, since the sand was originally in all probability 

 derived from the sea coast, though a portion may have come from the Indus 

 valley. The origin of the sand-hills is traced to the action of the south- 

 west wind which blows with much force throughout the area in the hotter 

 months of the year. The arrangement of the sand-hiUs in long ridges, parallel 

 to the direction of the prevailing wind is shewn to be an anomaly difficult 

 of explanation. Many of the sand-hiUs are of great antiquity and it ap- 

 pears possible that the long ridges may be due to a process of wind denuda- 

 tion, the intervening hollows having been swept clear of sand by the wind. 

 The existence of sand-hills throughout the desert is simply the consequence 

 of the want of any streams or rivers to wash the sand back again into the 

 sea. 



2. Notes on tlie InTiahitoAiU of the Nicobars. — 5y F. A. de Roepstohpf,. 



Candidate of Philosophy^ Copenhagen, Extra Asst. Superintendent 



Port JBlair and Nicohars. 



[Eeceived May 12tli. Eead 5tli July.] 



It has for a long time been known that there existed in the interior of 

 the island of Great Nicobar one or several inland tribes. They were con- 

 stantly spoken of by the coast people and by the inhabitants of the other 

 islands, but no Eiu-opean had ever seen them. Pastor Rosen, the Danish 

 Resident at the Nicobars 1831-34, mentions them in his book on the Ni- 

 cobars.* 



Admiral Bille describesf how he, with some of the officers of the expe- 

 dition in two boats, went up the Galathea river and came " to a place, 



* Erindringer pamit Ophold pan de Nikobarske Oes, &c. ; KjoLenliavrL (Copenlia- 

 geu) 1839. 



t Corvetten Galathea's Jordomseiling ; Kjobenhavn 1849, vol. I, p. 342). 



