260 
LATERITE OF VOLCANIC ORIGIN— ITS USES. 
have evidently been subjected, this ore was 
very much comminuted, and the more minute 
particles contributed the greater portion of the 
ferruginous paste, so characteristic of all the 
rocks around. 
To the eastward of the lake, in the low 
grounds, masses of the laterite jut forth 
from the soil ; and no other description of 
rock is to be seen in any direction. 
On Colonel Cullen’s property, on the east 
side of the lake, a trench has recently been 
cut, ten or twelve feet deep, and thirty or 
forty feet long. The first five or six feet 
from the surface consist of a red clay, con- 
taining a few fragments of the red conglo- 
merate sandstone, some nearly a foot in 
diameter, and, here and there, a piece of 
the ochrey iron ore. The sub-stratum is a 
yellowish, tenacious clay, v.dth no imbedded 
pebbles. An even line of demarcation dis- 
tinctly divides these two deposits, which do not 
at all blend into each other. 
At the south eastern corner, the nearest 
point of the laterite formation to Madras, 
there are numerous pits, where the rock is 
quarried to furnish material for the repair 
of the roads. After penetrating several feet 
of gravel, they come upon the solid laterite, 
which is broken up with a crow-bar, for which 
the employment of very great force is ne- 
cessary, the mass being previously softened 
by the effusion of water. It no where is of 
the soft consistence of the laterite of Malabar, 
as described by Buchanan and Babington. 
The laterite in this locality (No. 21) 
varies in no respect from that to the north- 
ward of the lake. It is all of the true com- 
pact kind, and I no where saw the large 
masses of conglomerate sandstone imbedded 
in the clay, witnessed in the nullah ; nor 
was there any appearance of stratification. 
The same kinds of imbedded rock frag- 
ments were found also at this spot, with 
the following additions : 
1st. Granite, composed of quartz, felspar, 
and mica: a single, small, angular fragment 
(No. 22). 2d. Sienite, or sienitic granite, 
composed of quartz, felspar, and hornblende; 
a large angular piece, in a disintegrating 
.state (No. 23). 3d. A line grained green- 
stone ; a large fragment (No. 24). These 
were found among the fragments, which the 
workmen had produced by their operations 
in the pits, and I cannot say whether they 
were derived from the gravel or the com- 
pact laterite. 
I have met with no calcareous matter in 
the localities 1 have visited, though 1 made 
particular enquiries on this point, as Dr. 
Heyne mentions the existence of that mineral 
at the Red Hills.* I picked up a single 
fragment of botryoidal kankar, to the south 
of the lake, but no where found it in situ. 
At the top of one of the lower eminences, 
imbedded in the gravel, about a foot and a 
half from the surface, I found fragments of a 
* Tracts on India, p. 114. 
rude pottery, the composition of which is of 
the coarsest kind, being a dark green paste, 
containing numerous grains of quartz 
(No. 25). These fragments, thirty or forty 
in number, were irregularly disposed, some 
pieces being vertically placed, others hori- 
zontally, shewing a confused arrangement 
in the gravelly matrix. This circumstance 
proves the gravel to be of recent origin. 
Dr. Benza informs me that fragments of 
pottery, of precisely similar composition, are 
found in the cairns on the Neilgherry Hills. 
It appears to me to resemble none of modern 
manufacture.” 
Mr. Cole confirms the opinion given by 
Mr. Malcolrason of the non-fossiliferous 
character of laterite, which he considers as 
sufficient proof of its volcanic origin, and he 
thinks that the existence of imbedded frag- 
ments of crystallized rocks by no means mili- 
tates against the eruptive theory, as portions of 
the rocks traversed by the volcanic rent may 
be thrown out. As building material and for 
road making on the McAdam system of 
formation, Mr. Cole states that the laterite 
is of great value. We cannot conclude this 
review without expressing our opinion of Mr. 
Cole’s ability and research, or acknowledg- 
ing the great pleasure we have experienced 
in the perusal of his and Dr. Benza’s valu- 
able papers, to which we shall recur in our 
next. 
Art. IV. — Cultivation of Cotton, By W. 
Bruce, Esq. Remarks on the culture of 
Cotton in the United States of America, 
Capt. Basil Hall’s Travels. Remarks 
on the best method of cultivating Neiv 
Orleans Cotton. Ibid. Regarding the 
cultivation of Cotton, Ibid. On the 
cultivation of Cotton in Central India, 
By Baboo Radkakant Deb. Obser- 
vations on the culture of Cotton in the 
Doab and Bundlecund, By W. Vin- 
cent, Esq. On the artificial produc- 
tion of new varieties of Cotton, By H. 
PiDDiNGTON, Esq. On the method used 
in Cayenne to preserve the Cotton plant. 
On a specimen of Cotton gathered in 
the Boglepore district from a shrub in 
its wild state, by F. Hunter. 
