The Old Red Sandstone of Antrim

The Old Red Sandstone of AntrimAuthor(s): James WaltonSource: The Irish Naturalists' Journal, Vol. 5, No. 2 (Mar., 1934), pp. 38-41Published by: Irish Naturalists' Journal Ltd.Stable URL: http://www.jstor.org/stable/25532296 .

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88 The Irish Naturalists' Journal. [Vol. V,

none surpass, which, coupled with his readiness to assist either

by action or word, made him a delightful companion. Further more, he possessed a fund of humour and never was he known

to give offence, nor did he take it readily. It may truly be said that he passed beyond without leaving one who could speak of him in anything but appreciative terms. Few men could

equal him as a raconteur and still fewer had the gift of imparting such an abundance of ripe wisdom.

S. A. Bennett was buried in the old churchyard at Lawton in East Cheshire on 12th February, amid surroundings of natural

beauty. To his relations we offer our full sympathy. J. A. S, S.

Noxe : A portrait of S. A. Bennett appeared in, I.N.J., vol. Ill, no. 12,

pi. 17, November, 1931.?Ed.

THE OLD RED SANDSTONE OF ANTRIM.

By James Walton, B.Sc.

Distribution and Lithology.

The Old Eed Sandstone of Antrim extends in a broad ridge from Cushendun in the north to Cushendall in the south and then up the Ballyemon Glen. The beds dip at all angles from 30? to 70?, although the dip is usually high and the strike is due S.W. and N.E.

The most northerly outcrop is at Cushendun, where the rock is a massive pebbly conglomerate with a preponderance of quartzite and vein quartz pebbles. Cushendall porphyry occurs rarely and sub angular masses of mica schist, hornblende schist and gneiss are also present. The beds are particularly well developed at the entrance to the caves. Lenticular bands of fine-grained, laminated sandstone also occur and extensive quarries are worked

in these beds at .Cave House where they show their maximum

development. Minor faulting, accompanied by slickensiding, and jointing are prominent features.

Farther south along the coast the feeds become finer in

texture, more felspathic and chloritic, and consist of .alternating layers of greenish grits and conglomerates and deep red, fine

grained, laminated sandstones. The fine-grained beds contain blocks of coarser grit, whilst the conglomerates contain an abun dance of pebbles of the finer material together with a minor

percentage of quartzite and porphyry pebbles; all this is evidence of contemporaneous erosion. Current-bedding, ripple marks and sun-cracks are common features of these beds. Calcite veins are also plentiful and are accompanied by a bleaching of the red sandstone. Chlorite is confined to the cracks and joints in the finer beds and a layer of chloritic material occurs along all the joint planes.

Nearer Cushendall the beds become coarser until they eventually consist of only large rounder! boulders, the interspaces



March, .1934.] The Irish Naturalists' Journal. 39

between which are infilled with coarse sandstone. The pebbles are almost all of Cushendall quartz porphyry but the percentage of these pebbles decreases as the beds arc traced to the west and north, and in a quarry u little eusi ol Tieveragh the ratio of quartz porphyry pebbles to quartziie is only 1 to $. This

particular quarry shows the following section: ?

ft. ins. Sundstone with few quarfczite boulders ... 2 6

Laminated mudstone ... ... ... 0 2

Conglomerate ... ... ... ... 6 0

Sandstone ... ... ... ... 2 0

and is separated by a fault from a quarry a little to the south which shows about 20 feet of coarse white felspathic grit.

In the Ballyemon Glen the beds vary from coarse red grits to very fine red mudstones with thin bands of small quartzite pebbles and towards the base they pass into a conglomerate consisting almost entirely of angular fragments of hornblende schist and mica schist.

Belationship to Other Formations.

The Old Bed Sandstone rests unconformably on the mica schist

_-?-?w-^ .r-1 and many sections of

?<*^?~~^-a|3^^<w the junctions are ex

\^ ^+** "^ -^y^^Y posed along the mm>r ^_

J!$^\r ^western boundary, v^ "ji^^^r* ?*T* especially in ia stream

^ ^vl^c7?*^r^J Inst east of Drum ^ JX^j^ ^^V*V A nacur Cottage and a

__-w4/?v- %yj*+ iittie w^st ?f ci?^hs ^ ^Â *<\ ̂ sHy/^ Lower C1) as well as in

? ^^-Wfiêl *w4*~

tihe Ballyemon Glen ~~~

~~~Jrl^v A J%t~~mwmm where it thins out.

^^^SaA^^St**"^11 At the.head of

^ S^f /"^^^Pcos, Ballyemon Glen the

Jp\ H nml^ 01d Eed Sandstone'

r^" / /3 Jp^^-V* dipping at 40?, is ^$Zq py^f; rVs-wi. overlain by the

Nrt:7 l^^sE&\" ' *'

:r Triassic Sandstone,

Sr^'^'/^îrX^^ dipping at 5?, and

|l^v/7sL^ both these beds are of

^fs^y.^, :v^v/c^^ 4r?. \\ :j;-1 s]mj}ar lithologioal

h-*-%? -*-** SuJj ^

character. The Chalk mmmm fjnobfcbk oia iu* 5<ii<nv?n? -Rwtr$

x ' also rests unconform

i^ fciovm w* ably on the Old Bed

^S: Uwir ^^û- Sandstone at the head

3i^l:rw4 ?f Ballyemon Glen, JL. oia -r4<l sûô** whilst the latter is

ii^*V?L? faulted up against the "^ o?>? ?rô?5 F'<^ 1* felstone porphyry at

-****** Cushendall. A little to the west of Cushendall the porphyry protrudes through the Old

Bed rocks as a small isolated boss. At Limerick Point the Old



40 The Irish Naturalists'Journal. [Vol. V.

Eed bandstone is traversed by a dolerite dyke and also a little to the west of Cushendall by another dyke and these have resulted in changing the colour of the sandstone from red to yellow.

The old basaltic vent of Tieveragh also traverses the Old Eed Sandstone. Eohleder has suggested that Tieveragh is merely the remnant of a basaltic sheet, ^> but the steeply plunging sides and the fact that the centre differs in appearance from the outer

part indicates that the Survey were correct in describing it as a volcanic neck.

Age.

The Old Eed Sandstone of this area has been correlated on

lithological grounds with the Dingle beds and Glengarifi3 grits of Southern Ireland.GO Consequently they are considered to be the equivalent of the Fintona beds of Tyrone and the Lower Old Eed Sandstone of Scotland.(3) Although this is quite justfiable and probable, yet there is no pakeontological support.

Mode of Origin.

The Geological Survey has suggested that these beds are shore deposits, whilst similar beds in Tyrone have been ascribed to a lacustrine origin b$? Nolan, but on closer examination it will be found that neither theory is applicable. In neither case would one expect coarse, current-bedded sandstones; the littoral origin does not account for the laminated mudstones, and the lacustrine

theory does not account; for the coarse conglomerates. The nature of the beds indicates deposition on wide plains of coarse out wash gravel and boulders carried down by torrential rivers from the mountain valleys. Gregory and Barrett have compared the conditions of deposition with those of the shingle rivers of the Southern Alps of New Zealand which have spread coarse sand and pebble beds over the Canterbury Plains, so building up the plain by the confluence of these deltaic fans.<4> During the major part of the year the rivers are reduced to many small branches that flow in constantly changing courses over beds of

shingle miles in width and the shingle is more conspicuous than the water. Eeaches of the river are often cut off, forming ox-bow lakes.

Applying this theory to the Old Eed Sandstone of Antrim we see that it could easily have been laid down in this manner

by two river deltas, one river draining the area to the south and

consequently carrying porphyry boulders and the other river

flowing from the north-west and carrying quartzite boulders

(fig. 1). The distribution of the two types of boulders suggests that the delta of the latter river was by far the larger, although a large part of the other delta would be in the area now occupied by the sea. These deltas have been indicated in the accompanying

map, and they would give rise to the beds of coarse conglomerate. The ox-bow lakes would result in the formation of laminated

muds, giving rise to the thin beds of laminated mudstone which are to be seen in many sections. The finer beds in Ballyemon

Glen represent the southern margin of the delta of the river



March, 1934] The Irish Naturalists' Journal. 41

carrying quartzite pebbles but, owing to the fact that no similar beds occur in the north or east, it is quite probable that the delta extended much further north than the present Old Eed Sandstone. Only the southern half of this delta is preserved, whilst only the western margin of the delta of the porphyry bearing river remnins.

REFERENCES.

(1) iMem. Geol. Surv., Ireland, Sheet 14, pp. 12-13, 1886, Dublin.

(2) Rohleder, H. P. T., Geological Guide to the Giant's Causeway and the North Coast of Antrim, p. 8, 1929, Belfast.

(3) 'Nolan, Joseph, "

On the Old Bed Sandstone of the North of

Ireland,'* Quart. Journ. Geol. Boc, 'No. 144, p. 534, 1880.

(4) Gregory, J. W., and Barrett, B. H., General Stratigraphy, p. 100, 1931, (London.

ZOOLOGICAL NOTES.

THE LAST IRISH WOLF.

I believe it is generally accepted that the last wolf in Ireland is

supposed to have been killed in the Knttekmealdown Mountains, between

Tipperary and Waterford, in 1770 (Irish NatqJS, p. 95, 1924). I recently came across the following letter which w&s^mhlished in The Field of

September 18th, 1885, and seems to have been overlooked. It is from

Capt. G. A. Graham, the resuscitator of the Irish Wolfhound!, and runs as follows : "In answer to the query of your correspondent J.W.D., though I am unable to speak about the black-and-tan pack he alludes to as existing (?) in the West oi Ireland, I can inform him that the grandfather of the present Mr. Watson Of Ballydarton?a well-known master of hounds in Co. Carlow?kept a pack of hounds for wolf-hunting, and that he killed his last wolf at Myshall, close to Ballydarton, about 1786."

According to Scharfi (Irish Nat. 31, pp. 133-6, 1922) the last wolf is

variously given as having been killed in three different places; one in the south (presumably the Knockmealdown Mountains), another near Glenarm, Co. Antrim, and the third at Wolfhill, three miles from Belfast.

Capt. Graham's letter is reprinted in Dogs : their History and Develop ment, by Edward C. Ash, vol. 1, p. 226, 1927.

Public Museums, Liverpool. NORA FISHEK.

REVIVAL OF AN OLD ESCALLOP FISHERY.

Of late there has been a revival, at various places on the County Down

coast, of the old escallop industry which at one time, over half a century ago, formed the main source of livelihood for the fishermen, of Carrick

fergus, Bangor and Portaferry. At that time, too, Jersey fishermen came north to Strangford Lough and worked the escalloo and oyster beds near the bar. Since then there has been very little dredging for Pecten maximus until about four years ago, when Groomsport fishermen found a productive bed off Ballymacormick Point and have since worked it successfully.

A couple of years ago two Portaferry fishermen, urged by the father of one, an old man who remembered the Channel Islanders working The Bar beds, started dredging there with surprising results, and now these beds are being worked by both Portaferry and Portavogie boats. As a result of a survey car?ied out last summer by our Fisheries Department, other productive beds were discovered, including one off Black Head, Co.

Antrim, another off Annalong, Co. Down, in a position known as "

the old oyster bank," and an especially large bank, about eight miles seaward of Quintin Bay, Ards, Co. Down, in 22 fathoms. As this fishery is carried on mainly from November to

April, when herring fishing and trawling



The Old Red Sandstone of Antrim

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