'Transactions of the Bombay Geographical Society, from September 1850 to June 1852. Edited by the Secretary. Volume X.' [‎46] (67/458)

Xlvi PROCEEDINGS OF THE SOCIETY.
and the cliange is hastened by cultivation: it is distinguishable at the surface,
from the numberless rents, cracks and fissures with which it is traversed. It
abounds with a totally different species of kunkur from that found in the yellow
clay—ofagreyish blue colour, assuming the most fantastic forms,and almost always
attaching itself to some piece of wood, straw, or other vegetable nucleus. It
m^de an excellent water cement when burnt, powdered, and sifted, settling
in the course of three or four minutes.
Kunkur found in the blue clay beds of the Flats, which extend under the shelLgrarel ftisdl
concrete of Mahim Wood, Sewree, the Esplanade, &c.
It has been collected along tlie line of the embankment as ballasting for the
railway. Specimens of the tubes had been formerly laid before the Society:
they consisted of a series of coatings of calcareous spar-—they seemed to be encrusta
tions in perforations made by some species of worm or borer in the rotten man
grove roots with which the blue clay everywhere abounded. The roots themselves
Were occasionably to be met with tolerably entire in the line of the railway, but
were not very plentiful: the prevalence of the tubes, which were to be found over
nearly all the lower portions of the island, unless where shell-gravel, loose
or indurated, prevailed, seemed proof sufficient of mangrove roots having exist*
•d, though now disseminated in our soil and lost.
Tubes found in the perforations 'of the rotton mangrove "roofs embedded in the blue clay
formati n. No perforations or tubes such as these have ever been met in with in the roots
of recent mangroves, however much decayed. They are supposed to arise from the infihra-
tion of wate r charged with lime, such as generally prevails everywhere during the monsoon.
The tube* vary from a quarter to three quarters of an inch in diameter—they are often a
a couple of feet in length, though they can rarely be taken out more than six or eight
inches in one piece. The walls of them vary from a few lines to a tenth of an inch in
thickness. They are generally crystallised in layers, of which there are from twenty to
thirty discernible under a magnifier : they are of a pinkish white eolour externally.