"What I have called indurated clay is not the mineral so called by Mr.Kirwan (...). It is diffused in immense masses, without any appearance of stratification and is placed over the granite that forms the basis of Malayala. It is full of cavities and pores, and contains a very large quantity of iron in the form of yellow and red ochres. In the mass, while excluded from the air, it is so soft, that any iron instrument readily cuts it, and is dug up in square masses with a pickaxe, and immediately cut into the shape wanted with a trowel, or large knife. It very soon after becomes as hard as brick, and resists the air and water much better than any brick that I have seen in India (...). As it is usually cut into the form of bricks for building, in several of the native dialects it is colled the brick-stone (Itica culla). Where, however, 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 (...). The most proper English name would be Laterite, from Lateritis, the appellation that may be given to it in Science." in (EN) Robert Cole, On the Geological position and association of the Latrite, or Iron Clay, formation of India, in The Madras Journal of Literature and Science, IV, 1836, pp. 100-102. URL consultato il 24 agosto 2009.
