126 Alfred Carpenter — The Swatch of no Ground. [No. 2, 1885.] 



remarkably little change, but close off the Rivers Hughly and Mntla 

 the banks have extended southward over a mile. 



When the ' Investigator' trawled in the Swatch last March the 

 bottom mud was found to be exceedingly soft, and consisted of a dark 

 green ooze largely mixed with shells of pteropods. Life here was com- 

 paratively scarce, only some annelid worms in muddy tubes and some 

 bivalve shells being found in the deeper portions, though at the sides, 

 on the sloping banks, several fish, Macrurus and small sharks, and some 

 shrimps and several other species of Crustacea were found. The mouth 

 of the Swatch rises somewhat rapidly from about 900 to 600 fathoms 

 with a bottom temperature of 43'°7 Fahrenheit. This is a little above 

 the average of open seas at corresponding depths, but, considering that 

 it is in Lat. 20° N. and that the water has presumably come from the 

 Antarctic Ocean, the difference is intelligible. The depth of 600 soon 

 decreases to 450 fathoms, at which depth a channel runs nearly up to 

 the head of the Swatch and carries the cold water northward, for at 

 100 fathoms at the head the temperature was as low as 56° though 

 the surface at the same time shewed 81°. 



The temperatare at the bottom between the Andamans and Ceylon 

 in 2100 fathoms is only 33.°7 Fahrt. corrected, this being in Lat. 8° N". 

 There is probably a deep valley trending up the west centre of the Bay 

 of Bengal, and the ' Investigator ' will annually add to our information 

 of its configuration. The position of the Swatch would be about in the 

 continuation of this valley, which is the main line of depression between 

 India and Burma, its northern extension being now filled with deltaic 

 deposits. Although the actual ground of the Swatch is of these same 

 deposits, and so of comparatively recent formation, the feature is in a 

 great measure due to the conflict of the same terrestrial waters, to the 

 erosive action of which in bygone times the rock- valley itself must be 

 in part attributed. 



