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III.—Glacialoid or Re-arranged Glacial Drift

Published online by Cambridge University Press:  01 May 2009

Extract

In many places in Ireland, but conspicuous in the S.E. portion, there is a Glacialoid drift (that is, a drift very similar in aspect to some of the typical Glacial drift). This drift will be found in places above the shelly drifts of Wicklow and Wexford, and has led Prof. Harkness, F.R.S., to believe that in those counties there is evidence for two distinct periods of glacial drifts, one below and the other above the shelly drift. His classification has been adopted by Mr. A. Bell and others; still there does not appear to be evidence in Ireland for two distinct ages of glacial drift, separated by an interval, represented by sub-aqueous accumulations (sand, gravel, marl-clay, &c.), and the reasons for this conclusion will be given in this paper.

Type
Original Articles
Copyright
Copyright © Cambridge University Press 1874

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References

page 111 note 1 Palælig;ontology of the Post-Glacial Drift of Ireland, by Bell, Alfred, Geol. Mag. 1873, Vol. X. p. 447.CrossRefGoogle Scholar

page 112 note 1 Moraine drift, called Boulder drift in my early papers on the Irish drifts.

page 113 note 1 Sir H. James records shells at a height of 400 feet on the Forth Mountains, Wexford. There would, however, seem to be a mistake in the figures, as Mr. Wyley, during his survey, did not observe them, but states they are not to be found above 250 or 300 feet, and the drift on the higher portions of those hills is a rock atritus in which shells could scarcely occur.

page 113 note 2 On the borders of the counties Limerick and Tipperary, fringing the high land Slieve Phelim], Glacialoid drift is found capping and interstratified with the Esker-period gravels.

page 114 note 1 In typical Boulder-clay drift there may be subordinate portions in which the blocks stand on edge. This, however, seems always to occur in places where we may suppose an iceberg or shore-ice was aground on the Boulder-clay drift, and shoved the blocks up on end.

page 115 note 1 Since the above was written, my colleague, Mr. E. T. Hardman, has drawn attention to a beach of this period near Tramore, co. Waterford.

page 116 note 1 The Æolian drift or blowing sand has not been mentioned in connexion with these accumulations, as such sands may.be of any age, some being as old as the later part of the Glacial Period, having been formed while the moraine drift was accumulating, while portions are forming at the present day.

page 116 note 2 There is a section exposed in the old sea-cliff at Dunleary Harbour, east of the Salt-hill Hotel, in which, as seen from the railway, a Boulder-clay-like drift overlies a considerable thickness of gravel. The base of this cliff is a huge kitchen-midden. Consequently it could not he examined. Therefore I cannot say if the upper portion of this section is typical Boulder-clay drift, or if the underlying gravels are similar to the shelly gravels in the adjacent country to the south.