506
of the Copper Bolt, by transference from one object to another,
as each gets destroyed; but even if this is done it will still
be necessary to refer to mean sea level if any gradual local
alteration in the level of the earth's crust is to be detected.
18.
I have plotted a number of sections of
Hunghor Bay, from the soundings of January, 1887, and those of
January, 1905, tazen for His Excellency by Commander D'Arcy,
superimposing the cue upon the other, for the purpose of showing
the changes that may have occurred during the interval of 18
years. The area of sea bed covered by Commander D'Arcy's survey
is too uneven to show small changes well. Section 'C' shows Do
appreciable change of average depth; Section 'B' shows a balance
on the side of deepening; Section 'A' shows an apparent deepening
of several feet over a great part of its length. I have ascer-
-tained from the Manager of the Dock Company that dredging
operations have not been carried cut to a greater distance than
100 feet from the front of the Docks. A slight apparent deepening
might be attributed to natural scouring, or to discrepancies in
the surveys; but the apparent deepening in this case seems to be
toc great to be so accounted for.
19.
It would be well to have a few test sec-
-ticos taken, when opportunity offers, for the purpose of ascer-
-taining what alterations of the sea bed are taking place. 1
would suggest taking soundings on the lines shown in blue on
Charts E-1140 and E-4077. It would be a fairly big job to do this
correctly, and there is no use in doing it otherwise; but it seems
to be necessary, for the present at least, to have a survey party
sent out from England to make a complete survey ((15 and 20)).
20.
As to the suggestion that borings should be
taken ((18)), 1 think, with all due deference to the Consulting
Engineers, that as it is proposed to dredge the stuff, and to no
great depth, samples of it may very properly be got by dredging.
Good
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