1836.] 



Later it e } or Iron Clay, 



101 



knife. It very soon after becomes as hard as brick, and resists the air 

 and water much better than any bricks that I have seen in India. I 

 have never observed any animal or vegetable exuviae contained in it, 

 but I have heard that such have been found immersed in its substance. 

 As it is usually cut into the form of bricks for building, in several of the 

 native dialects it is called the brick-stone (Itica culla). Where, how- 

 ever, by the washing away of the soil, part of it has been exposed to 

 the air, and has hardened into a rock, its colour becomes black, and its 

 pores and inequalities give it a kind of resemblance to the skin of a 

 a person affected with cutaneous disorders ; hence, in the Tamul lan- 

 guage, it is called Shuri cull, or itch-stone. The most proper English, 

 name would be Laterite from Later it is, the appellation that may be 

 given to it in Science."* 



In many places throughout his Journal, Buchanan adverts to the 

 extensive prevalence of the laterite in Malabar and Canara, sometimes 

 over " an amazing extent of surface," to use his own words. It is de- 

 scribed by him to be universally found overlaying the granite, and he 

 no where mentions it as associated with any trappean rocks, or with 

 sienite, porphyry, or an5 r other rocks that are classed with that 

 family. In a paper, on the minerals of the Rajniahal cluster of hills, 

 published in the Gleanings in Science for January 1831, from Dr. Bu- 

 chanan's M.S.S. occurs the following passage : " South from Mansa 

 Chandi, at Jajpar on the borders of Virbhum and Murshedabad, there 

 is a hill, which consists chiefly of a clay, readily cut with a knife, but 

 which, on exposure to air, becomes somewhat hard, and is evidently of 

 the same nature with the brick-stones of Malabar, which I have de- 

 scribed in my account of Mysore. It is, however, vastly inferior in 

 quality. This clay has a very strong resemblance to the slaggy stone 

 of Mansa Chandi ; and some parts of it, that have hardened into stone, 

 are scarcely distinguishable, except by wanting the slaggy appearance. 

 They must, however, be considered as a kind of breccia, as they con- 

 tain ferruginous nodules in an argillaceous cement." 



The next mention, in point of date, of the mineral we are treating of 

 is, by Mr. Benjamin Babington,* in a paper on the Geology of the 

 Country between Tellicherry and Madras. The whole of the following 

 passage, descriptive of this rock, I transcribe, making no apology for 

 its length as it is very characteristic. 



" The face of the country in general below the ghauts is hilly. These 

 hills are low, of a rounded form, and composed of the ferruginous stone 

 so peculiar to India, called by Buchanan laterite. In this porous rock, 



* Journey from Madras through Mysore, Canara and Malabar . — By Francis Buchanan, k. », 

 Vol. 2d, p. 436 and p. 440. 



* Traas. of the Geological Society of London, Vol. 5, part 2d, p. 329, 



