'The Transactions of the Bombay Geographical Society. From January 1865 to December 1867. (Edited by the Honorary Secretary.) Volume XVIII.' [‎74] (101/268)

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Ixxiv
PROCEEDINGS OP THE
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Eesolution.— Two quite different subjects, and the consequences of two quite
distinct agencies, are included in the article of the Bombay Saturday Review and
the letter "of the Bombay Geographical Society.
2 The silting up of the northern and eastern parts of the Gulf of Cambay,
caused by the large quantity of alluvial matter brought down by three large
rivers, especially in the S. W. monsoon, when the waters of the Gulf are ponded
back by southerly gales, and again the erosion of the eastern coast of Kattyawar,
and deepening of the channels there caused by this large body of water having
to escape by the western shore of the Gulf, have both been going on in historic
periods. The effects of these agencies are evident,—-the causes are not doubted.
3 . But the elevation or subsidence of the Bunn is a much more recondite
subject; the facts must be established more accurately than they as yet hay©
been; and the causes are not easily explained.
4 . With regard to the Gulf of Cambay, the Government will be glad to adopt
the suggestions of the Bombay Geographical Society, and have the surveys of the
Coast and the soundings Measurements of the depth of a body of water. taken in such detail as the Society may approve.
5. But as to the more interesting question presented with the Bunn, it does
not appear to the Governor in Council that watching the line of coast now, or
learning its past history, will give the requisite information as to the raising or
depression of the land; for encroachments of the sea at one place and siltings up
and recessions at others may arise, as is shown by Dr. Oldham in the case of the
Gulf of Cambay, from many other causes.
6 . The soundings Measurements of the depth of a body of water. recommended by the Geographical Society cannot be
taken with the accuracy required for these observations, and must depend on the
state of the tide varying both diurnally and periodically, and influenced by winds
and seasons.
7. The mean level of the sea (in the scientific acceptation of that phrase) is
the only reliable datum to which observations for changes in land level should
be referred, and the only basis on which any good opinion could in future times
be formed as to elevation or depression.
8 . There should, therefore, be a course of accurate tidal observations taken
through two lunations at a point on the south coast of Kattyawar, and also at a
point as far into the Bunn as possible to which tide has free access.
9. These should be referred to bench-marks made in permanent masonry
pillars close to high water mark, and those marks should be connected to the
Bvelling ^ 1110 ^ 8 ^ 1 Statl011S ° f tlie Great Trigonometrical Survey by careful
^ tans oe connected with all the stations throughout the Bunn
and Kattyawar and with one another ; and in future years if a change occur in
the level of the Bunn stations, this will be checked not only by the mean level of
e sea, u y the southern tidal bench mark, which would not probably be
subjected to any change.