14 
Records of the Geological Surrey of India. 
[vol. III. 
to some parts of the Cuddalore sandstones as seen near Cuddalore, and like them appears 
completely unfossiliferous. In the Cortelliar cliffs the following section is exposed:— 
Lateritic conglomerate ... ... ... ... ... 3 to 4 feet. 
Mottled gritty sandstone ... -. ... ... 6 „ 
Quartzosc grit of buffy white and brown colors, becoming whiter and 
coarser grained downwards, very friable; beds divided by thin 
partings of Kunkur ... ... ... ... 30 to 40 „ 
The base of the section is unfortunately entirely obscured by fallen masses, or by the 
water which here remains in a deep pool at the foot of the cliffs. 
It is not known what underlies these beds, so they can only he provisionally regarded as 
representatives of the Cuddalore sandstones. The gritty sandstones west of Poonamallee 
which Mr. H. F. Blanford was disposed to refer to the same supra-cretaceous position have 
yielded a few fossils of unmistakeahly Rajmahal (jurassic) character. 
No representatives of the cretaceous group being as yet known to occur within the 
limited Madras area I pass on to review the different members of the 
Rajmahal oe Jueassic Rocks. 
Although occupying superficially a lesser area than the lateritic rocks, the Rajmahal 
beds are of infinitely greater geological importance and deserve considerable attention. 
Like the lateritic rocks, the Rajmahal beds are scattered about over the country in a 
number of detached areas and patches divided from each other by alluvial valleys or by 
bands of overlying lateritic strata that have escaped denudation. From this broken up 
condition of the formations addl'd to the absence of really good sections it is difficult and in 
some cases almost impossible satisfactorily to correlate the different formations occurring in 
several patches. 
For convenience sake it will he better to consider the several distinct patches in four 
groups, ignoring as much as possible the intervening covering formations of younger date. 
It is only in the three northern of these four areas that the base of the Rajmahal beds is 
seen, resting on the gneissic rocks along the foot of the western flanks of the Sattavedu and 
Alicoor hills and of "the low plateau east of the Areonum railway junction. 
In the Sripermatoor area the base of the series is nowhere seen owing to the great 
thickness of the surface deposits. Owing partly to the peculiar shape of the ground, but 
still more to the general softness of the rocks and to the consequent enormous accumulations 
of debris covering the surface, no section exists showing the true relations of more than small 
portions of the Rajmahal series, which renders any stratigraphical sub-division of the entire 
series very difficult and uncertain. A provisional sub-division into two groups has, however, 
been proposed, based mainly on lithological differences. 
To one group consisting of coarse well consolidated conglomerates and sandstones the 
name of Sattavedu group lias been given, from the fact of these beds having been first 
studied-by my colleague, Mr. King-, in the Sattavedu hills. 
The other group, consisting of shales, clays, and gritty sandstones and unconsolidated 
conglomerates, we have called the Sripermatoor group, from its most important members 
occurring under and around the town of Sripermatoor. 
The SatUiredu Group .— In the Sattavedu area the entire series of rocks met with 
consists of alternate hands of conglomerates and sandstones many hundred feet thick. These 
beds extend southward into the Alicoor hills area (under the valley of the Narnaveram river) 
and form the eastern and loftier half of the hill group. The entire eastern base of both the 
hill groups is covered up by lateritic conglomerates and sand, by which any extension to the 
east of this series is completely masked. 
The chief petrological character of the members of this series is the prodigious coarseness 
of the conglomerates which are made up of large well rounded smooth pebbles of quartzite with 
a small number of similarly waterworn masses of granitoid gneiss firmly cemented together 
by a varying cement which is sometimes argillo-ferruginous, ferrugino-arenaceous, or silicio- 
calcareoiis. In some of the sandstone beds in the Sattavedu hills Mr. King discovered the 
few plant remains, amongst which was part of a recognizable Dictyopteris frond, proving the 
true Rajmahal character of the beds which contained it. In the southern extension of the 
