3T4 
MANGANESE DEPOSITS OF INDIA : GEOLOGY. [ PaRT II : 
on this hypothesis is thus analogous to that of the Swedish 
lake ores in process of formation at the present day. 
3. T. H. Holland i, writing from experience of the Southern Indian 
laterites, suggests that the rock is formed in situ, the energy 
necessary for the breaking up of the silicates being derived 
from the vital action of organisms, ordinary and special. He 
fui'ther explains the development of concretionary structures 
by suggesting that ' in compounds where a constituent is 
loosely held, the "crystalline affinity" by which physical 
molecules tend to imite and form crystals may be more 
energetic than the chemical affinity'. 
4. E. W. Wetherell ^, writing particularly of the Bangalore and 
Kolar districts in Mysore, supposes that the laterite of this 
area is of detrital origin and was formed by the washing of 
the decomposed surface detritus of the surrounding elevated 
ground into a lake, where it got mixed with non-lateritic 
material only to a small extent, and was subsequently cemen- 
ted by the action of segregative tendencies, due to the pre- 
sence of some organism in the lake, such as one allied to Gir- 
vanella. As Mallet also allows for the washing of detritus into 
his lakes, this theory is only a variant of Mallet's, giving the 
preponderance to mechanical instead of to chemical deposition. 
5. Lastly J. M. Maclaren has recently published a paper 3 in which, 
relying mainly on a very clear section at Talevadi in the Bel- 
gaum district, he advances the view that lateritic deposits 
are derived from mineralized solutions brought to the surface 
by capillarity, and, are essentially replacements (either 
mechanical or metasomatic) of soil, or of rock decomposed in 
situ, or of both ; the contents of the solutions being derived 
from the rocks at and near the surface. 
The Laterite of the Yeruli Plateau. 
Leaving out of consideration the high-level laterite deposits of the 
first type, of which I have had no field experience, and also passing over 
1 Geol Mag., Dec. IV, Vol. X, pp. 68-09, (1903). 
2 Mem. Mysore Gcol. Dep., Ill, Pt. I, pp. 24-27, (1906). 
3 Oeol. Mag., Dec. V, Vol. Ill, p. 546, (1906). 
