Hostname: page-component-76fb5796d-45l2p Total loading time: 0 Render date: 2024-04-27T11:53:29.351Z Has data issue: false hasContentIssue false

On the Microscopical Examination of some Bracklesham Beds

Published online by Cambridge University Press:  17 March 2016

Get access

Extract

In Vol. I of the ‘Geologist,’ at page 249, was published a paper on the preparation of sands, clays, and chalk, for microscopical purposes, under the heading of “Geological Manipulations;” and, as both pleasure and geological profit are to be obtained from the exact examination of various fossil-bearing deposits, both as to their constituents and their contents, I beg to offer you an example of the results of such an examination of some tertiary beds from Bracklesham. These notes I have had by me several years, and their short-comings are so great in some respects that I should not send them, were it not that they may serve as a plan to some young careful observers who might feel inclined to enter upon the strict examination of some definite series of fossiliferous strata. What the series under notice is deficient of, is a statement of the exact relationship of these several deposits, examined nearly twenty years ago. I received the materials at that time from a friend who was collecting “Bracklesham fossils,”—a term which will be more definite, now that the Rev. O. Fisher, F.G.S., has indicated the exact limits of the Bracklesham formation.

The specimens were chiefly, I believe, from Bracklesham and Selsea; but some may have been brought from the Isle of Wight. By the presence of certain fossils, however, in some of the deposits, their exact place may probably be determined. However deficient in these stratigraphical requirements the following account of the deposits may be, they will serve the purpose here intended, namely, to show young beginners what to look for in sands and clays. Instructions have been already given as to how such materials are to be examine, in the first volume, p. 249.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1862

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

page 59 note * See Report of the Geological Society's Proceedings, Dec. 4th, 1861.

page 60 note * The clays and sands in this paper are described as they appear when dry.

page 60 note † The specimens No. 3, 4, and 5 being given in lots of 3840 grains, Nos. 1 and 2 (which were examined in lots of 480 grains) are given also as 3840 grains for the sake of comparison. With regard also to Nos. 1 and 2, their lists of fossils must be regarded as less perfect in relation to the other specimens, on account of the small quantity of the deposit examined.

page 60 note ‡ For the list of fossils, see the table further on.

page 60 note § The sands of all the lots are chiefly composed of green grains (silicate of iron ?) and quartz sand. Further details respecting the relative size, angularity, etc., of the sand-grains in the several specimens ought to have been given.

page 61 note * The shells in this specimen are larger than in the other lots. In the latter the shells, etc. found in this examination were chiefly of small size, although larger shells, of course, are sometimes abundantly distributed in the mass of the beds.