Unpublished paper, 'On the beds of chert in the Carboniferous limestone of Ireland' by Edward Hull and E [Edward] T Hardman

Description

After reviewing what has been published by previous authors on the origin of chert-beds, and showing that much remains to be done in this department of petrology, Hull proceeds to describe the geological position of the principal chert zone of the Carboniferous limestone of Ireland, showing that, while bands of chert occur at intervals throughout this formation, the highest beds immediately under 'The Yoredale Shales' are especially rich in chert, and are frequently entirely replaced by this mineral. In these beds coralline, crinoidal, and other marine forms are frequently to be recognized by the naked eye. Thin slices for microscopic examination, taken from various localities, extending from Sligo to Carlow, also show that even the most dense and compact masses of chert exhibit, under favourable circumstances, forms belonging to those marine animals (such as corals, crinoids, foraminifers, and occasionally molluscs) which build their shells or skeletons of carbonate of lime rather than of silica. The siliceous paste in which these forms are enclosed is found to be in a gelatinous state; and the forms are only to be distinguished by difference in depth of shade from the paste, the shells or skeletons having disappeared. The chemical analyses of these specimens by Hardman tends to show that the chert-beds contain various proportions of carbonate of lime as well as other minerals, so that a gradation from siliceous limestone into pure chert might be traced.

Annotations in ink throughout. Marked on front as 'Archives Nov 1/77'. Includes three plates of figures and one page of photographs.

Subject: Geology / Petrology

Received 16 March 1877. Read 26 April 1877.

Whilst the Royal Society declined to publish this paper in full, an abstract of the paper was published in volume 26 of the Proceedings of the Royal Society as 'On the nature and origin of the beds of chert in the upper carboniferous limestones of Ireland'.

Reference number

AP/59/5

Earliest possible date

1877

Physical description

Ink on paper

Page extent

48 pages

Format

Manuscript
Drawing
Photocopy