STTB-RECENT MARINE BEDS. 69 



southward, whicli is unfortunate, as it prevents one's tracing their connec- 

 tion with another series of sandstones which occur on the south side of the 

 spit. These latter beds which show a southerly dip of from 10° to 15° or 

 more, consist of hard massive sandstones of varying colour and composition. 

 In parts these sandstones are nearly purely silicious, in others they 

 are highly calcareous, because including a large percentage of commi- 

 nuted sea shells. In some places the sandstone contains no shelly frag- 

 ments, but consists solely of laminse of quartz and magnetic iron sand, 

 mixed or distinct, as the case may be. A general admixture of garnet 

 sand, sufficient in quantity to give the whole rock a ruddy colour, is com- 

 mon, but the garnet sand does not often form distinct laminse by itself. 

 Some beds are found in which a four-fold mixture prevails. The sand- 

 stones are best seen close to the surf by which they are occasionally 

 undermined. They have also been very largely quarried at some former 

 time. At the extremity of the spit an identical sandstone contains 

 many shallow little basins, in a good number of which a growth of coral 

 is now taking place. The question to be solved with regard to these 

 sandstones is whether they represent a true sub-aqueous deposit which 

 has been upheaved to an elevation of from 2 or 3 to 12 or 15 feet above 

 the present sea level, or whether they must be regarded as a local indura- 

 tion of the beach sand and overlying small dunes such as the sandstones 

 exposed at Manapadu and close to the Tiruchendur Temple and already 

 referred to above. I should incline to regard the Valimukkam and other 

 similar sandstones at many places along the Ramnad coast as indurated 

 dune sands like those at Manapad and Tiruchendur, were it not that in 

 Hameswaram island unquestionable evidence exists of a considerable 

 elevation of the land in very recent times, geologically speaking. This 

 evidence is afforded by existence of an upheaved coral reef, very extensive 

 indications of which occur round the northern coast of the island. This 

 reef will be described further on. 



A small patch of this hard sandstone fringing the beach was noticed 



The sandstone "quay" some miles to the westward at Narripurpattanam 



along tlie coast. (Nurripoorputnumchary), while long stretches of 



( 69 ) 



