PHYSICAL GEOGEAPHY. 



[Part T. 



The transformation of gneiss into laterite in these 

 localities has been attributed to the circumstance, that 

 those sections of the rock which undergo transition 

 exhibit grains of magnetic iron ore partially dissemi- 

 nated through them ; and the phenomenon of the 

 conversion has been explained not by recurrence to 

 the ordinary conception of mere weathering, Avhich 

 is inadequate, but to the theory of catalytic action, 

 regard bemg had to the pecuharity of magnetic iron 

 when viewed m its chemical formula.^ The oxide of 

 iron thus produced communicates its colouring to the 

 laterite, and in proportion as felspar and hornblende 

 abound in the gneiss, the cabook assumes respectively 

 a white or yellow hue. So ostensible is the series of 

 mutations, that in ordinary excavations there is no 

 difficulty in tracing a continuous connection without 

 definite hnes of demarcation between the soil and the 

 laterite on the one hand, and the laterite and gneiss rock 

 on the other.^ 



of Tamba-pannyo, ' copper-palmed,^ 

 from tlie colour of the soil. From 

 this circumstance that wilderness 

 obtained the name of Tamba-panni ; 

 and from the same cause also this 

 renowned laud became celebrated 

 under that name." — Ttjunouk's 3fa- 

 hawanso, ch. vi. p. 50. From Tamba- 

 panni came the Greek name for 

 Ceylon, Taprobane. Mr. de Alwis has 

 correlated an error in this passage of 

 Mr. Tumour's translation ; the word 

 in the original, which he took for 

 Tumha-panniyo, or ''copper-palmed," 

 being in reality tamha-vaima, or 

 " copper-colom-ed." Colonel Forbes 

 questions the accuracy of this de- 

 rivation, and attributes the name to 

 the tammia trees ; from the abun- 

 dance of which he says many vil- 

 lages in Ceylon, as well as a district 

 in southern India, have been simi- 

 larly called. {^EleiTii Years in Ceylon, 

 vol. i. p. 10.) I have not succeeded 

 in discovering what tree is desig- 

 nated by this name, nor does it occur 

 in jMoon's List of Ceylon Plants, 



On the southern coast of India a 

 river, which flows from the ghats to 

 the sea, passing Tinnevelly, is called 

 Tambapanni. Tambapanni, as the 

 designation of Ceylon, occurs in the 

 inscription on the rock of Gimar in 

 Guzerat, deciphered by Prinsep, con- 

 taining an edict by Asoka relative 

 to the medical administration of In- 

 dia for the relief both of man and 

 beast. (Asiat. Soc. Journ. Bemj. vol. 

 vii. p. 158.) 



^ From a paper read to the Royal 

 Physical Society of Edinburgh by the 

 Eev. J. G. Macvicar, D.D. 



^ From a paper on the Geology of 

 Ceylon, by Dr. Gardner, in the Ap- 

 pendix to Lee's translation of Ri- 

 BEYEo's History of Ceylon, p. 206. 

 The earliest and one of the ablest 

 essays on the geological system and 

 mineralogy of Ceylon Avill be found 

 in Davy's Account of the Interior of 

 Ceylon, London, 1821. It has, how- 

 ever, been corrected and enlarged by 

 recent investigators. 



