LAKE: GEOLOGY OF SOUTH MALABAR. 



rather a low terrace laterite, full of rounded quartz pebbles. So that 

 here again is evidence of a fluviatile origin. 



It is hardly necessary to describe any more areas of valley 

 laterite. In most cases the valleys are much better defined than the 

 Ponnani Valley, and the deposits are clearly fluviatile. There is a 

 very broad spread of laterite around Wandur, the origin of which is 

 not quite clear, but it is probably valley laterite. Other spreads 

 are found near Manje'ri, between Manjeri and Eddawannah, &c. 



Laterite not belonging to any of the three groups. — A few excep- 

 tional cases remain to be discussed. 



Near the Ghats several iron mines are worked and still more 

 were in operation some years ago. Some were visited by Dr. 

 Buchanan 1 when he was staying at Ang^dipuram. He states that 

 the ore is obtained from the laterite. It was so, perhaps, in some of 

 the mines, but most have been worked in gneiss. Those nearest to 

 Ano-^dipuram, however, in Mangada (Mungadda) amsam, do not 

 pass down into the gneiss. They have not been worked for a long 

 time, but very possibly they were the mines examined by Dr. 

 Buchanan. 



In the amsams of Porur 2 (Erna'd Taluk), Nemini, 3 and Arakkapa- 

 ramba* (Walluvanad Taluk), the mines have been worked in gneiss. 

 The iron ore, where exposed to the air, becomes converted into 

 laterite. At an old abandoned mine in Porur, there were veins of 

 laterite in the gneiss, which must at one time have been veins of 

 iron ore. In Arakkaparamba there is a sort of neck of laterite (late- 

 ritised iron ore) on the top of a hill, and the mines have been dug 

 down through this to the unaltered iron ore below. 



Under this heading must also be included taluses of laterite cover- 

 ing the slopes of laterite-capped hills. It is impossible to draw a 

 hard-and-fast line between this form and the valley and terrace 



1 Journey through Mysore, Canara, and Malabar. Madras reprint, 1870. Vol. II, 



p. 113. 



- 4 miles north of Pandikad. 



8 North-east skpes of Pandalur Hill. 



4 N ;rth-east slopes of Pranakod Hill. 



( 228 ) . 



