36 LAKE: GEOLOGY OF SOUTH MALABAR. 



the highest part of the plateau. One of the tributaries of the Bey- 

 pore now found its way through this and joined the Kadalhundi Ri- 

 ver. This is the river that flows by Pandika*d. The upper part of its 

 course is at a lower level than the part of the plateau through which 

 the gorge is cut. 



As the land rose above the sea its surface became decomposed and 

 at last lateritised. Valleys began to be formed in it long before the 

 present level was reached. The watercourses being short and the 

 slope slight, the valleys were broad and shallow, like those of the 

 undulating region at the present time and like the upper part of 

 the valleys of the gorge region. The depression in which New Ma- 

 lapuram stands is one of these old valleys. As the land rose, the fall 

 of the rivers near their sources became greater, and hence they cut- 

 deeper and narrower channels at the bottom of the old valleys, and 

 these channels are now the gorges. At the same time near the sea 

 they cut the shallow valleys of the undulating region. 



Since the land at the foot of the Ghats rose above the sea later 

 than the land round the central islands and the slope of the ground 

 was less, the rivers there have never cut gorges but only shallow 

 valleys. 



It was on the plain of marine denudation as it gradually rose from 

 the sea that the plateau laterite was formed; on the floors of the 

 old river valleys, the terrace laterite ; and on the floors of the new 

 valleys, the valley laterite. 



Economic Geology, 



The laterite is by far the most useful of the formations found in 

 Malabar. It is the great water-bearing stratum, and it supplies the 

 most useful building materials. 



The older laterite, from which all the clayey contents of the tubes 

 have been washed out 3 is very barren and supports nothing but grass, 

 oil seed, and a few small trees. In 1855-56, during the extension 

 of the Nilambur Teak plantations, several laterite hills were planted ; 

 but on these the teak completely failed. Fresher laterite, however, 

 ( 236 ) 



