104 



On the Geological characters of the 



[July 



with trap) which from thence extends as the overlying rock, with little 

 interruption, to the extremity of the Peninsula, covering the base of 

 the mountains, and the whole of the narrow belt of land that separates 

 them from the sea, exhibiting, a succession of low rounded hills and 

 undulations, and reposing on the primitive rocks, which occasionally 

 protrude above the surface, as at Malwan, Calicut, and some other 

 points, where granite, for a short space, becomes the surface rock ; 

 from the main land, the laterite passes over into Ceylon, where it re^ 

 appears, under the name of Kabuk, and forms a similar deposit, of 

 some extent, on the shore of that Island. Passing onwards from the 

 western or Malabar Coast, round the extremity of the Peninsula, we 

 leave this extensive iron clay formation,, and crossing the granitic 

 plains of Travancore, which are strewed with enormous blocks of 

 primitive rocks, we arrive at the termination of the chain." 



Now it seems rather a loose expression to say that laterite ia 

 contemporaneous with trap, which is considered to be of every geolo- 

 gical epoch, from very early eras, to a period subsequent to the depo- 

 sition of the chalk. If it is meant that the laterite of the south is con* 

 temporaneous with the trap of the Deccan, 1 cannot but think that 

 such a mode of generalization is jumping fo conclusions, without any 

 sufficient data whereon to found the assertion. We have no where 

 any accounts (that I am aware of) of any resemblance between the two 

 on the western side of India, except that they each, in their separate 

 localities, overlay primitive rocks. But, if it had been so ordered that 

 secondary formations, containing organic remains, had covered the pri- 

 mary formations of the south, the same argument might have been 

 employed for maintaining their association and contemporary relation 

 with the trap of the north, that the laterite is now said to hold. 



Besides, the circumstance of its being an overlaying rock by no 

 means marks the indentity of the two ; for, according to the establish- 

 ed opinion of the origin of the trap rocks, there must be veins and 

 dykes through which the matter composing them was erupted from 

 helow. Now we no where hear of a vein of laterite ; unless, indeed, 

 that title should be erroneously bestowed on a vein of cavernous, 

 hsematitic iron ore, one of the productions which occasionally obtains 

 the character of true laterite, I am inclined to think, for it is a terra 

 very laxly applied in Indian geology. 



I look upon the statement of Dr. Voysey, quoted above, as by no 

 means invalidating the opinion of the detrital origin of laterite. (t Wacke 

 being an earthy kind of trap, and containing the same ingredients as 

 basalt, may be produced in some instances from the disintegration of 

 the latter rock ; and w r hen that is the case, its further decomposition 

 would give rise to a rock no wise different from clay."* If this be the 



* Encyclopedia Metropolitana, Art. Geology, by Phillips and Daubeny, page 753. 



