IGNEOUS ROCKS IN THE SOUTHERN PART OP THE PENINSULA. 629 
strictly speaking, the line of fracture running 
N. and S. crosses diagonally the lines of 
stratification. We see from this that there 
are mountain ranges having their stratifica- 
tion parallel with their direction, and others 
having it oblique ; it will follow also that if 
disruption take place across lines of subvert- 
ed strata, a variously composed ridge will 
be the result ; whereas, if the dislocation 
proceed parallel with the subverted strata, 
there will be in consequence a continuity 
of the same rock elevated. This is a rule 
that will be found to hold good in most 
cases as applied to primitive strata, and, 
where secondary ranges occur, the subjacent 
rock is more to be considered as the true 
mountain ridge than the overlaying crust. 
The Gujunder Ghur hills, for example, 
although a sandstone range, are based on 
granite ; owing their superior elevation to 
the rising of the granite underneath : an- 
other example is the sandstone of the Nag- 
gery hills. It has been remarked that while 
the primitive trap ranges, with the exception 
of that on the western side (namely, the 
Ghauts), have a tendency N. E. and S. W., 
inferior ranges supporting secondary strata 
run more N. and S. — it requires observation 
to prove how far this is the case. 
Throughout the southern part of the 
peninsula, igneous rocks greatly prevail, 
there being scarcely a trace of aqueous 
strata ; and among the primitive rocks 
clay-slate is wanting, although it is found 
in abundance further north : in certain 
places clay-slate and limestone tracts, of 
the transition series, are of vast extent, and, 
considering the almost invariable presence 
of valuable metallic ores in such districts, 
they are not the least interesting in a com- 
mercial point of view. 
In the Konkan north of G-oa the elevation 
of the Ghauts is clearly pointed out as sub- 
sequent to the formation of laterite ; the 
table-land is covered with a thick crust of 
this substance, as well as the lower level of 
the Konkan ; and hills, which appear rising 
from the low ground as detached portions 
of the table-land, are flat-topped, with a 
crust of the same laterite, while their slopes, 
like the general escarpment of the Ghauts, 
are covered only with a loose debris. 
The Carnatic, and several other similar 
tracts, occurring along both coasts, are, as 
granitic plains, surprisingly level : the slight 
tertiary diluvium with which they are co- 
vered, cannot be considered as a principal 
cause of this uniformity, for the rock itself 
is everywhere found near the surface ; every 
appearance here indicates that the granitic 
formation has at one time been a great 
deal more flat than it is generally understood 
to have been. The Neeigherries rise from 
a plain nearly as level as the Carnatic, and 
their summit bears evident marks of having 
been once on a level with the Mysore and 
Coimbatore plains. Like elevated regions 
in other parts of the world, the Neeigher- 
ries shew also traces of a diluvial current ? 
that is, the gravel and loam are arranged in 
such a manner as could only take place by 
deposit from water ; the gravel being lowest 
in a thin stratum by itself, with the lighter 
loam covering it, to the thickness of several 
feet, and without gravel. The carbonaceous 
black cotton soil occurs here as on the 
plain, and it is found under the general 
gravel line as well as above, shewing it to 
have been lodged among the broken strata, 
before the passage of the later diluvial cur- 
rent over the surface : the indications are 
that this current has passed before the hills 
attained their present elevation, which last 
seems an event so recent, as to be only an- 
terior to the formation of kankar. As no 
secondary strata occur near the Neeigher- 
ries, none need be expected on their sum- 
mit ; but, on the eastern Ghauts at Naggery, 
sandstone is found, and serves to point out 
that the hills there have been elevated since 
the sandstone period. It is probable that 
the other parts of the Ghauts havejbeen 
raised about the same time : every thing 
tends to show that the elevation of these 
ranges is a comparatively recent event. 
Geologically viewing these chains in 
conjunction with the table-land, it appears 
that the surface, nearly as far to the east- 
vrard as Salem, has been forced to a con- 
siderable height, with the Cauvery ranges 
