THE CHARACTER OF THE ROCK OF THE NEELGHERRIES, 
623 
on which it rests. Thus, it is ferruginous on 
those places where iron ores are found ; 
quartzy and silicious above the thick veins 
of quartz, which intersect these rocks. 
Below the detritus, in almost all places on 
the hills, Dr. Benza found a thick stratum 
of an ochreous red earth, which occasionally 
assumes both the appearance and the com- 
position of lithomarge, and for this reason 
the author hereafter indiscriminiately deno- 
minates it either lithomargic, or red earth. 
In general, this red earth is of a mottled 
colour, or streaked with different hues of 
red, yellow, crimson, white, and grey or 
brown. It feels unctuous to the touch, and 
crumbles into dust when pressed between 
the fingers. It does not form a paste with 
water, but subsides to the bottom of the 
vessel. The different colours of this earth 
are separate and distinct, having a decided 
line of demarcation, so as to show that they 
are produced by the decomposition of 
separate and distinct minerals. This red 
lithomargic mould is evidently the result 
of the decomposition of two of the rocks, 
which almost exclusively form the Neel- 
gherries ; viz. the sienitic granite, and the 
hornblende rock, or primitive greenstone. 
Dr. Benza, after visiting and examining 
the summits of some of the highest hills, 
found a variety of pegmatite forming many 
of the most prominent rocks on them. 
Such are the summits of Doodabetta, Elk 
Hill, Kaitee pass, some of the peaks of the 
Koondah, and probably many other places 
which he did not visit. It is undoubtedly 
to some of the erratic blocks and rolled 
masses of this rock, or to the decomposition 
of those beds of pegmatite, into which the 
true granite of the high hills seems to pass, 
that the porcelain earth is owing. Of these 
blocks, still in an undecomposed state, 
many are seen in the valley of Kaitee ; 
derived, in all probability, from the 
summit of Doodabetta, or from that of 
the rock of Kaitee where the pegmatite is 
seen in situ. Our author states that the por- 
celain earth is not to be confounded with that 
which results from the decomposition of the 
pure felspar veins, so frequently seen in the 
sienitic granite. He found it between two 
large blocks of decomposing sienitic granite, 
or rather hornblende rock, with garnets, 
close to the bund of the lake. Alluding 
to magnetic iron ore, he states that the 
two places on the Neelgherries, where 
he had seen this ore very rich in metal, 
are, one near the village of Vartsigiri 
(Kotagherry), and the other close to, and 
traversing, the lake of Ootacamund in two 
places. Tim specimen from Vartsigiri 
is very compact and rich in metal. He 
took it from a large block, probably the 
outgoings of a thick bed at the southern 
extremity of the valley, at the other end of 
which tlie village stands. The appearance, 
composition, and proportion of the ingre- 
dients of this magnetic iron ore are very 
different in different places ; nay, in the 
same vein. Dr. Benza mentions that it 
is the belief of some people, that owing to 
the similarity of the rocks, of the detritus, 
and of the quartz veins, of the Malabar 
coast, and of these hills, gold may be found 
in this last, as well as in the former. Iron 
ores are so common on these hills, independ- 
ently of the oxides of that metal contained 
in the minerals forming the rock, that many 
springs of water are of the chalybeate class=^. 
The next species of iron ore on the Neei- 
gherries is the hrematitic, forming immense 
beds, and sometimes whole hillocks, among 
the hornblende rocks, and sienitic granite. 
The most extensive formation of this 
hsematitic ii’on ore is seen on both sides of 
what Sir F. Adam calls Scotland Valley. t 
The rock of the Neelgherries is by no 
means so cavernous, and has not so many 
tubular sinuosities as 'the laterite of the 
Carnatic, Northern Circars, &c. ; it seems 
also to be richer in metal, and, what appears 
to constitute a marked difference, it is en- 
tii’ely divested of any quartz, or sandy par- 
ticles, which abound so much in the laterite 
of other places. Dr. Benza alludes to the 
opinion of Dr. Heyne, that in the laterite 
* Baikie’s Observations on the Neelgherries, 
page 14;. 
+ Sir Frederick Adam, Governor of Marlras, 
called it i>y that, name, on acco\mt. of a vesf^m- 
blance he saw in it to some place in Scotland. 
