342 



0?i the Lateritic Formation. 



[Oct. 



stead of containing about ninety per cent, of iron as lispmatite does, they 

 had only, I think, six per cenf. The specimens sent by Mr. Gilchrist 

 have a more jaspeny appearance than those on the hills, and are I think 

 of the quartz family, either a jasperry clay iron ore, or a ferruginous 

 opal, some specimens passing into a coarse kind of jasper, and into se- 

 mi-opal and chalcedony. 



To terminate, then, this part of the subject, the connections pointed 

 out by Dr. Benza himself, between the specimens on the hills, and those 

 sent him from Hoonsoor, which as just observed were found associated 

 with, and passing into, jasper, semi-opal and chalcedony, tells much in fa- 

 vour of his hEcmatitic iron ore being an altered quartz rock, and not the 

 true harmatitic iron ore o-f mineralogists. The peculiar appearance of la- 

 terite has been by many referred to the influence of water, and the very 

 same structure has led others again to a belief in igneous action. This 

 igneous aspect I believe to be the result of oxydation. Water, by lodging 

 on a rock or percolating through it, may assist in its decomposition, and 

 the enormous quantity of water falling on the western coast might, in some 

 measure, account for the almost universal prevalence of laterite on that 

 coast. In the neighbourhood of Cannanore nothing but laterite is seen, 

 accompanied by series of rounded lithomargic hills, some of them a little 

 flattened at the top and resembling reversed tea cups. This laterite has 

 at a distance the appearance sometimes of granite, hornblende rock, or 

 gneiss. What appears to be a trap dyke is found on inspection to be la- 

 terite, and in many places its similarity externally to decomposing gneiss 

 was so strong, that I never was satisfied till convinced by the hammer. 

 Buchanan mentions that laterite on the coast overlays granite ; a proof, 

 1 should imagine, of its being derived from it ; and this connection is 

 found in various other parts of the country. The cantonment of Canna- 

 nore is situated partly on a cliff overhanging the sea, which cliff varies 

 in height and terminates on the north and south by a beach. Along the 

 coast a few rocks are seen elevated above the water, and blocks of the 

 same nature, having fallen from the clitF, lie below it, upon which the 

 waves break. The cliff and blocks are of laterite, and resemble external- 

 ly the water-worn sandstone formation of Bermuda. On the sea-shore I 

 picked up specimens exactly like lithomarge, but indurated, and one or 

 two of a very sandsto'ne aspect and of a reddish colour. The greatest 

 part of the coast towards Tellicherry is low, with much sandy soil, and , 

 the natural accompaniment, numerous cocoa-nut trees. Some way before 

 reaching this place, there is gneiss, containing much black mica, and at 

 Tellicherry there is a great deal of rich reddish yellow soil, close to the 

 sea, and hornblende rock is lying on the beach, and extending some way 



