'Transactions of the Bombay Geographical Society, from September 1850 to June 1852. Edited by the Secretary. Volume X.' [‎215] (348/458)

X
• "NOTES,
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NOTE A. p. 177.
EVIDENCES of a general vibration, or descent and subsequent
UPHEAVEMENT OF THE LAND ALL ALONG THE SHORES FROM SUEZ TO
ARRACAN. (THIS NOTE REFERS TO P. IfS, THE QUOTATION HAS BEEN
OMITTED BY THE PRINTER).
Whoever lias read the previous paper on Volcanoes will already have seen
that the upward and downward movements, on our shores, have been phenomena of
frequent, and some of them, of recent occurrence. We are not assured that the
upper part of the Bay of Bengal, as high as Chittagong, was effected by the same
series of convulsions, as on three successive occasions lifted the Tenasserim shores
and the islands of Cheedooba and Ramree into terraces ; but there is the strongest
possible presumption that it was so. Ten years after the occurrence of (he last
of these we know that Chittagong and the surrounding country were depressed, so
that we have precisely similar movements as those about to be described, only
that the last of the series had been inverted in point of order; the upheav,„
ing taking place first and the depression following, instead of the depression
occurring first and the upheaval subsequently. In the frequent borings for water
which took place at Calcutta, between the year 1301 and 1837,—during which
time the ground had been penetrated to depths from 70 to 380 feet,—a succession
of strata were met with, indicating most clearly that that portion of the delta had
been alternately a salt marsh, covered with mangroves, and a fertile plain watered
by rivers, and on which deer and other wild animals were able to sport and
browse. The existing site of Calcutta, little as it is elevated above the level of the
inundations, could only have attained its present altitude by upheaval. Whenever
ground reaches the limits of ordinary floods its rise becomes almost imperceptibly
slow; when it gets beyond the level of extreme inundation it can never rise at all,
save by force from beneath. Appearances, the same as those found at Calcutta, were
found in boring at Madras 5 and beds of shells, covered with recent alluvium, are
found at the present day, all along the the level portion of the Coromandel Coas^
At Madras itself this has, of late, been transformed into selenite ; at Bombay into
masses of calcareous spar. So far back as 1797 Captain McKenzie called attention
to the terrace of sea gravel and shells bordering for the space of 500 miles
the low flat shores of the Carnatic, as an evidence of the recent recession of the sea
—Ihe theory until lately very generally maintained I and all along the shores
°f Manaar the same phenomena were observed the cemented shells (littoral
concrete) forming a portion of Adam's Bridge, It appears more than probable
that the bulk of the Islauds which skirt the Malabar Coast were, at