CHAPTER XIX. 
G'E.OLOGY— continued. 
Manganese in Laterite. 
General — Low-level latei ite — High-level laterite — Theories as to origin of high- 
level laterite — The Yeruli laterite — Lateritio manganese -ores — Lateritoid — The 
Talevadi occurrence — Jabalpur and Goa — List of localities — Economic value — 
Sandur — Distribution — Structure and working of — Mineral composition — Chemical 
composition. 
General. 
In many parts of India the geology is obscured by an overlying cover- 
ing or cap of a curious rock characteristic of tropical chmes. This rock 
consists essentially of a mixture of hydrated 
Origin of the term. -j t ■ j i ■ -^-l 
oxides of iron and alumina, with often a con- 
siderable percentage of titania. It is the rock known to Indian geolo- 
gists as laterite. This word and its latin equivalent, lateritis, both 
meaning literally brick-stone, were invented by F. Buchanan, F.R.S., 
being derived from the Latin word later, a brick, in allusion to the custom 
of cutting this rock into the form of bricks for building purposes ; this 
is on the analogy of several South Indian vernacular names also 
meaning brick-stone. 
Much attention has been devoted to the study of this rock by Indian 
Division into low and geologists, and it is evident from their writings, 
high-level laterites. that there are several varieties. Nevertheless, 
they can all be classed into two main divisions. These two divisions are 
the low-level laterite and the high-level laterite ■ and it was to the low-level 
varieties of the Malabar coast that the term laterite was first applied by 
Buchanan, the extension of the term to include the high-level varieties 
being due to subsequent writers. This classification depends solely on 
the elevation at which the rock is found and is quite independent of its 
origin. Nevertheless, it so happens that the larger proportion of the 
low-level laterite is partly of detrital origin, and the larger proportion 
of the high-level laterite of non-detrital origin. 
Low-level Laterite. 
The low-level laterite is found mainly in the low-lying coastal region 
on the east and west sides of the Peninsula. Perhaps the larger propor- 
tion of low-level laterite is of detrital origin and formed by the mechanical 
' 'A Journey from Madras through the countries of Mysore, Gamua, and Malabar,' 
II, p. 441. London, (1807). 
