LATE GLACIAL AND POST-GLACIAL SHORELINES
IN NORTH-EAST ANTRIM
D. B. PRIOR
The Queen's University of Belfast
INTRODUCTION
This paper examines the evidence for fluctuations of sea level in glacial
and post-glacial times, between Ballygalley and Ballycastle in north-east
Ireland (Fig. i). Stranded shorelines have been recorded in this area
by a number of authors, including the Geological Survey (1886), Praeger
(1897), Coffey and Praeger (I904), and Movius (1937, 1940, 1942, 1953).
Wright (1928,1937) has considered some of the raised beaches in relation
to their regional setting in the north-west of the British Isles, and more
recently Stephens (1957, 1963, 1965, 1966) has published accounts (some
in co-authorship with F. M. Synge) attempting to elucidate the field
evidence.
Intensive investigations were carried out by the author in 1964-65
on the Antrim coast, and a variety of features were mapped, including
erosional notches (and associated terraces) in both drift and bedrock,
raised beach deposits and areas of drift-free rock which may have been
washed by the sea at higher levels.
Heights were obtained by use of a small hand level, working from Ordinary High Water Mark (Summer). Using a graduated staff and Dumpy
level, O.H.W.M. was related to Ordnance Datum at two places and was
found to be at 12.72 ft and 12.35 ft OS>. and the average (12.5 ft) was used
to relate all the elevated features to Old Irish Datum (c. 8 ft below English
datum).
The coastline between Ballygalley and Ballycastle is dominated by
rugged cliffs rising 400 ft above the modern shore, which form the eastern
edge of the Antrim Plateau. At intervals the cliffed coastline is interrupted by deep valleys incised in bedrock. Associated with these are small
areas of coastal lowland in drift, though generally an extensive low coastal
fringe is lacking. Evidence of former marine transgressions is fragmentary,
especially where recent marine erosion has been most intensive and the
features are best preserved in the more sheltered embayments of the
coastline.
173
RATHLIN ISLAND
MULL OF KINTYR
Church Boy
©
Rue Point
Fair Head
Murlouqh Bay
Torr Head©
Tornamoney
Cushendun ®
Cushendo// ©
Woterfoot
A'rdclinis
Newtown
Burnside
Rinqfad
Hunferi Pf
Corn Iough ©
idkilly
ME.IRELAND LOCATION MAP
Gtenarm
Drumnogreogh House
Ballygaltey
Ballyqalley Hd
KEY
Drains Bay
••—••..•• lOOO' CONTOU«
^ I T I ARHOY MOXA1NE
•CD
f^rr>
*¿¿s
Larne
SITES «EFEI»:D TO m TEXT
IKEA SUSKEKCEO AT TIME OF
HIGHEST BEACH
Fig. 1. The coastline oí north-east Antrim, and the sites where measurement of
stranded shorelines have been made. The baseline B-B is drawn parallel
to the baseline used by Stephens (1966), which was judged to cross the
isobases for the late glacial and post-glacial raised beaches nearly at rightangles.
174
DRUMNAGREAGH
House
PORT
Late-glacial marine benches (L.G.I.)
Post-glacial marine bench
(Pre-Boreal or L i )
Ro
°d
I
23 ft
•
Shingle
bar(L2)
(
*
\
f f
DRAINS
BAY
B
Late-glacial marine
bench (L.G.1.)
Post-glacial marine cliff
53 to 56 ft /
/
notch at 28to30ft
J
(U.J
J
CUSHENDUN
22(t
\ Shingle bars(L2)
Rockport House
notch at 34 ft
notch at 69 ft
Glenmona Lodge
notch at 24 to 27 ft
Post-glacial shingle bars
I (Pre-boreal or L.I.)
37
Cushendun
i i ne^
warren
i
i
•.•••.": Knocknacarry
Gravels at 60 to 65ft
Fig. 2. Schematic coastal profiles irom Drains Bay, Drumnagreagh Port and
Cushendun, Co. Antrim. The diagonally ruled sections (in A and B) axe
composed oí landslipped masses oí basalt, chalk and clay, with some boulder
clay.
175
SITES INVESTIGATED (FIG. I )
I.
BALLYGALLEY
At the site of the village, there is an extensive bench (in drift and
land-slipped debris for the most part) at 56-59 ft O.D. This bench extends
inland as far as the Old Corn Mill, half a mile from the coast. The notch
is not sharp but a height of 59 ft O.D. was recorded at it. The coast
road at Ballygalley makes use of a low bench which has a notch at 38-30
ft O.D. This is weakly developed and is obscured by houses. West of
Ballygalley castle there is a fragment of a low terrace at 20 ft O.D. (i.e.
about 8 ft above the modern beach).
2. DRUMNAGREAGH PORT
The site of Drumnagreagh House, three and a half miles north of Ballygalley, overlooks a series of well developed benches cut in glacial till and
landslip material (Fig. 2). The highest of these extends inland around and
behind the house at an average elevation of 65-70 ft O.D. A good notch
below the house occurs at 76 ft O.D. The front edge of the bench at this
point is at 67 ft O.D. A lower bench extends from the modern shingle
beach to a notch at 30 ft O.D., and about 9 ft above O.H.W.M. there is
a low arcuate ridge of shingle now completely grassed over.
3.
GLENARM
About a quarter of a mile inland from the village of Glenarm there are
three distinctive river terraces (Chapman 1960) with height ranges of
78.3 ft., 53.7 ft and 31.1 ft O.D. (Heights represent the back of the
terraces.) All of these terraces are very flat and this series can be traced
some four miles inland, to a point where the longitudinal gradient of the
valley floor increases from o° to 4 0 .
At the Cloney, immediately north of the village, there is a shingle
ridge trending north-northeast to south-southwest, parallel to the modern
beach. The ridge crest reaches a height of 37 ft O.D. and would appear to
be flanked by a low bench at 20 ft O.D. on the seaward side, which is
followed by the modern coast road.
Excavations in this ridge by Movius (1937) revealed the following
stratigraphy :—
(a) Humus (35 cm),
(b) Beach deposits (1.85 m),
(c) Till (unknown thickness).
Shells of Littorina littorea and numerous flint implements were found
176
in the Humus horizon. The excavated section revealed that the deposits
of horizon (b) were of two types, with the junction between coarse rounded
cobbles of chalk, basalt and flint and underlying fine sands and gravels
at 1.4m. below the surface. Archaeological implements of late-Larnian
"type were present, and, although shells were rare, Littorina littorea and
Cyprina islándica were identified. It is not clear whether the implements
were associated with the upper horizon of (b), the lower sands and gravels,
or both. However, Movius concluded that the deposits constituted a
storm beach formed during the Late-Atlantic period, and he correlated
horizons (a) and (b) with the upper horizons at Glendun (see Site 9).
The presence of shells of Littorina clearly identifies the beach as postglacial.
4. CARNLOUGH
At the head of Carnlough Bay there is abundant evidence of both marine
erosion and deposition that extended to an upper limit of about 65 ft
O.P. Fragments of a bench cut in till can be seen at the site of the village
of Carnlough, a good notch being recorded at Grentara Terrace (62 ft
O.P.). The bench extends inland behind the village for a distance of a
quarter of a mile around the mouth of the Cranny River. To the southwest, Prurnourne House (52 ft O.P.) is situated at the base of a stranded
cliff in till. There is also an extensive flat lowland with an average height
of 59-63 ft O.P. in the Glencloy river basin but the notch in this case is
not distinct.
Near the Bay Farm, in the banks of the Glencloy river, sections revealed
chalk, flint and basalt pebbles in a sandy matrix over the dark brown/grey
till of the area. Some pebbles exhibit a high degree of rounding and chatter
marks. Further, the townland north of the Glencloy river, on the 60 ft
bench, is known locally as Stonyhill and cultivation reveals a topsoil of a
sandy texture with frequent rounded pebbles. Both these deposits are
only found in association with the high bench. The high sea-level would
appear to have cut the bench in till and deposited a veneer of sandy gravel.
Seawards of this high bench there are accumulations of sand and
gravel, forming ridges which run parallel to the modern shore in a northnortheast to south-southwest direction across the head of the bay. There
are two main ridges and the crest of the highest, which runs from Harphall
House in the north to the base of the steep slope by the Ballyvaddy
road, achieves heights of 34-41 ft O.P. The Glencloy river has breached
the ridge and at the Bay Farm, where the main ridge divides in two, there
is a 20 ft section in rounded sands and gravels with good bedding dipping
seawards at average of io° true dip. This ridge does not appear to contain
177
either shells or archaeological implements at depth, although the latter
are found frequently in the uppermost horizons. It is not clear whether
these sands and gravels rest directly upon till or conceal other deposits,
such as are seen at Glendun.
There is another parallel shingle ridge which extends from the mouth
of the Glencloy river northwards for a quarter of a mile towards Oscar
Lodge and it has a crest height of about 25 ft O.D. There are also scattered
fragments of erosional benches at lower levels, at the harbour in Carnlough
village, where there is a notch at 28 ft O.D., and behind the modern
storm beach in South Bay where there is a bench at 19-21 ft O.D. Marine
erosion has undoubtedly removed many of these lower benches, notably
north of Carnlough, where the coast road is supported by stone embankments. Modern mass movement at Straidkilly Point has also helped to
obliterate former benches.
5.
BURNSIDE AND
NEWTOWN
Two miles north of Carnlough, in the townlands of Bumside and
Newtown, there is a well-developed bench with an average height of
64 ft O.D. A height of 68 ft O.D. was obtained for the notch in till despite
the effects of hillwash and soil creep. The marine transgression penetrated
inland around a 100 ft high ridge which can be seen just north of Bumside
Bridge. Because of the asymmetrical character of the ridge, a slight dip
inland with a steep scarp towards the sea, it is thought to be one of the
many slumped blocks seen in this area, and this is supported by evidence
afforded slightly further north in Newtown townland where a stream has
cut through what is undoubtedly a shingle ridge formed against the edge
of a downthrown block of chalk.
A section through this shingle ridge reveals two pronounced notches,
at 33 ft O.D. and at 40 ft O.D. The upper horizons of the beach material,
consisting of highly rounded chalk and basalt pebbles with sand, achieve
heights of 60 ft. Between the two notches there is a horizon of dark brown
loamy clay, with sub-angular blocks of basalt and chalk (average thickness, 3 ft). This is considered to be a solifluction deposit developed under
periglacial conditions subsequent to the deposition of the lower gravels
at 33 ft and prior to the formation of the upper beach deposit, which may
indicate two distinct phases of the transgression.
At Newtown there is also a bench (notch at 28 ft O.D.) cut into this
shingle ridge. This bench is almost continuous along this part of the
coastline and is well seen at Bumside where it cuts into the front edge of
the high bench, and here, and further south at Ringfad, there is a small
bench with a notch at 20 ft O.D.
178
6. GAREON POINT
At Garron Point school there is a small bench at 32 ft O.D. cut in.
landslip material, which is associated with some small abandoned caves
in chalk at the road level. There is also a low raised shingle spit at 22 ft
O.D., 5 ft above the modern storm beach. Near the Post Office the chalk
appears to have been washed clean of drift to a height of 34 ft O.D.,
corresponding with a small bench at this height on the landward side of •
the coast road. However, it should be remembered that exposed bedding
planes in the chalk may simulate marine-eroded platforms.
At Ardclinis Bridge there are remnants of three benches cut in till
and landslip material. The highest of these has an average elevation of
about 63 ft O.D., but does not have a good notch. Benches with notchesat 34 ft O.D. and 23 ft O.D. were also recorded, the latter just below the
coast road.
7. WATERFOOT
The floor of Glenariff Glen lies below 50 ft O.D. for up to 2 miles inland,,
and according to the evidence presented above, must have been almost
completely submerged at the time of the highest sea-level. Direct evidence is lacking for wave action must have substantially diminished in
intensity within such an embayment and there are no good notches. However, at Redbay Pier a series of sea caves in soft Triassic sandstone show
that there have been at least two former sea-levels in this area. There isan upper set of caves with entrances (lip of cave mouth) at 54 ft O.D.„
and a lower set at the road level with entrances at 30-35 ft O.D. (Stephens,.
8. CUSHENDALL
Between Redbay Pier and Cushendall there is a high bench which isnot entirely flat but which has a general elevation of 60-71 ft O.D. The
notch is indistinct, again being cut in till, but this erosional bench may
be traced inland beyond the high road in the townland of Culbidag.
The bench has suffered from later stream erosion but its seaward edge issharp, especially north of Redbay Pier and west of Limerick Point.
It is difficult to trace at Cushendall, for on the north side of Cushendall
Bay there is a steep cliff in hard Old Red Sandstone against which the
highest sea-level must have washed, but without cutting a recognisable
notch. At Culbidag (65 ft O.D.) sections were recorded of 1-2 ft of rounded
schist, quartzite, chalk and basalt pebbles in a sandy matrix (possibly
beach deposit ?), overlying a red boulder clay containing chalk and schist179
At the golf course, due east of the village, a large shingle ridge is being
•eroded by the Ballyemon river. The crest of the ridge reaches a height
of 39-42 ft O.D., and like those at Carnlough and Glenarm is parallel to
.the modern bay-head beach. A section reveals the following stratigraphy :
(a) Humus (1 ft),
(b) Gravels (18 ft),
(c) Peat (c. 9 ft),
(d) Till ? (unknown thickness).
The gravels (b) closely resemble those at Carnlough in form, but have
:a high proportion of schist and Old Red Sandstone cobbles derived from
the local bedrock. No shells were seen. The presence of the peat deposit
(c), containing large tree branches and pieces of bark, is most interesting,
as is its thickness. A sample has been sent for C-14 dating, which should
.give a valuable indication of the maximum age of the overlying beach.
The base of the peat is not exposed but its depth was determined by boring
with a Hiller-type auger. It appears to overlie a red sandy deposit containing large amounts of schist debris. The origin of this deposit (d) is
not known but may be the upper layers of the local red till.
Between the beach ridge and the modern foreshore (at this point protected from erosion by a low sea wall) there is a bench with a notch at
29 ft O.D., which is also seen all along the coast between Limerick Point
.and Redbay Pier. At Limerick Point there is a small accumulation of
•shingle at 24 ft O.D., some 12 ft above O.H.W.M.
Steep rocky cliffs of Old Red Sandstone dominate the coastline between
•Cushendall and Cushendun. At Port Obe a small bay has been cut in the
«cliffs and a bedrock platform is seen at 23 ft O.D. This is overlain by a
beach deposit of rounded cobbles. The platform itself shelves seawards
.and the lower part is covered at O.H.W.M. by modern beach shingle.
-On the shores north of this inlet a small stack is associated with an in•distinct notch in bedrock at 25 ft O.D. Similar features are seen intermittently along this stretch of coastline but these features have not been
inserted on the shoreline diagram because it is not certain if the rock
".benches were cut in late glacial and post-glacial times (Stephens and
Synge, 1966).
•9. CUSHENDUN
In the lower part of Glendun, between Knocknacarry and the village
of Cushendun, there is a bench at 62-69 ft O.D. (Fig. 2). This bench is cut
.in till and it has been considerably eroded subsequent to its formation,
being best preserved on the valley sides. At Knocknacarry a section
jreveals 6-8 ft of sands and gravels forming a terrace level at 60 ft O.D.
180
This is composed of cobbles of quartzite, sandstone and schist in a sandy
matrix exhibiting crude bedding, and overlying a fed till. This gravel
terrace with a flat top at 60-65 ft O.D. was formed during the period of
the highest sea-level and can be correlated with the abandoned sea caves
in the Old Red Sandstone to the south of Cushendun (Movius, 1940).
The village of Cushendun is sited upon the Warren, a shingle ridge
complex which has a maximum crest height of 37 ft O.D. Excavationsby Movius (1940) and the identification of implements and shells, together with pollen dating carried out by Jessen (1940), prompted Moviusto offer the following interpretation and chronology for the stratigraphy :
(a) Humus (50 cm)—Post-Atlantic age,
(b) Upper Gravel (3.15 m)—Bay mouth bar (containing Littorina),
(c) Upper Lagoon silt (77 cm)—Atlantic age,
(d) Lower Gravel (3.58 m)—Coalescing marine spits,
(e) Lower Lagoon silt (46 cm)—Early Atlantic age (first stage of theLittorina transgression),
(f) Swamp Peat (10 cm)—Late-Boreal-early Atlantic age,
(g) Re-sorted Till (30 cm),
(h) Laminated Clayl
_,,. ,
, ,. ... ,
J
:./ „...
> thickness undetermined.
In addition to the features described, there is a small shingle ridge
(crest at 27 ft O.D.) south of Rockport House which parallels the modera
shore, and Rockport House itself stands on a bench with a notch at 34't
O.D. East of Glenmona Lodge there is a lower bench (notch at 24-27 ft
O.D.) with blown dune-sand covering it undergoing severe erosion.
10. TORNAMONEY POINT
A little way east ôf Tornamoney Point, where the stream reaches the
sea, drift appears to have been washed off the underlying schist surface
to a height of 80 ft O.D. At this height there is a good notch in till. There
is also a lower notch and undercutting of schist bedrock at 62 ft O.D.
Below this at 45 ft O.D. is the main limit of washed rock, where the drift
has been completely removed exposing buttresses of schist. Associated
with this particular washing limit is the inner edge of the lowest beach
deposit at 37 ft O.D.
11. TORR HEAD
To the north of Leckpatrick Point, in Portaleeft Bay, there is a small
bench with a notch at 80 ft O.D. cut in thick deposits of till. A sharp
notch was recorded at 81 ft O.D. just south of Altmore Burn. Also, just
181
•east of the coast-guard station there is a good washing limit at 80-82 ft
O.D. where superficial deposits have been removed, exposing the bedrock.
This washing limit can be traced horizontally to a small lens of gravels
at 75 ft O.D. in the head of the small inlet at Boat Port ; the deposit is
recorded on the 1/63360 Drift Sheet (No. 4) published by the Geological
Survey. It is composed of a very coarse angular deposit exhibiting some
bedding and containing a high proportion of local material, including a
Ted porphyritic rock which occurs in dykes south of Leckpatrick and as
•an intrusive boss at Glendun. This deposit is derived from the local
boulder clay and may be explained as part of a crude beach deposit, for
it lacks the character of typical fluvio-glacial outwash. A lower bench
^t about 30 ft O.D. is also present and there are three elevated stacks.
Between Torr Head and Fair Head there are some small benches around
.Murlough Bay (Drumnakill Church, plus 50 ft O.D.), but the coastline is
dominated by extensive landslipping and at Fair Head by screes developed
from the 200 ft dolerite sill. To the west of Fair Head the bold precipitous
cliffed coastline, with extensive tip heaps (from former coal workings)
combined with the exposed nature of the coast has meant that evidence
for former marine transgressions has either been removed or is extremely
poor. However, at Carrickmore Port, there is a terrace feature at 39 ft
O.D. This may not be a natural feature, but at Bath Lodge, one mile
east of Ballycastle town, there is a stranded cliff line at about 50 ft O.D.
and small remnants of a bench at this height may be seen at the North
Star Colliery. At Ballycastle modern dune sand obliterates the evidence
of former sea-levels.
12. RATHLIN ISLAND
At the eastern side of Church Bay, and on Rue Point, there are remnants
of low benches cut in till. At Ushet Port on the south-east side of Rue
Point there is an extensive bench in till at an elevation of about 30 ft
O.D. Hanna (1952) records marine gravels in this locality and also in the
townlands of Demesne and Glebe, where there is a notch at 33 ft O.D.
In addition, at Rue Point there is a washing limit at 69 ft O.D. (Synge
and Stephens, 1966).
DISCUSSION
The evidence presented above is plotted on a shoreline diagram (Fig.
3) following a method used by Stephens and Synge (1965), and here using
a base-line drawn through Ballygalley Head with an orientation 13J0
182
loo
loó
w
A
•
c
WASHED ROCK
SHINCLE
90
NOTCH
CAVES
T
BENCH
r
PEAT
SO
7O
60
50
tu
-A—TT T"TÎf
2O
OH.W.M. (SUMMER)
10
s
Bo
BASELINE DRAWN THROUGH Í A U Y C A U E Y
HEAD-ORIENTED
Q
/
-
I OF N
*•
Q
/
«f
MILES
Fig. 3. The shoreline diagram for the stranded shorelines between Lame and Rathlin Island, Co. Antrim.
OB «ET
east of north. From this diagram several separate shorelines of different
ages can be recognised.
The highest synchronous shoreline (L.G.i) was drawn using the marine
limit between Torr Head and Ballygalley and the set of benches and
notches cut mainly in drift at heights between 55 and 80 ft O.D. Beach
gravels at Newtown, Cushendun and Torr Head, and washing limits at
Tornamoney and Torr Head are also associated with this shoreline,
which has a tilt southwards of approximately 1 ft per mile. It would be
possible to draw a series of highly tilted shorelines (see dotted Unes
L.G.A., L.G.B., L.G.C., L.G.D.) between Ballygalley and Torr Head
which would indicate that the marine limit south of Torr Head is not
representative of a single synchronous transgression. But shorelines
L.G.A. and L.G.B. would then be tilted at about 3 ft per mile and it is this
high degree of tilt which throws considerable doubt on the validity of
such an interpretation because comparable tilts are not known elsewhere
within the British Isles (Sissons, 1962, 1963 ; Sissóns and Smith, 1965 ;
Stephens and Synge, 1965, 1966).
On the north coast, between Fair Head and Ballycastle the marine
limit is markedly lower than that seen to the south of Torr Head. At
Bath Lodge (one mile east of Ballycastle) and on Rathlin Island the marine
limits are respectively 50 ft and 69 ft, and these heights do not appear to
fit the tilted line of synchronous shoreline L.G.i. Thus, the marine limit
in north Antrim cannot be everywhere associated with à single transgression. Another shoreline (L.G.2.) has therefore been drawn which
post-dates L.G.i. The height difference and time relationship can be
explained by examining briefly the manner of the déglaciation of this area.
Preliminary examination of the drifts in east Antrim has shown them te»
be derived from northward moving Irish ice emanating from the ice-shed
centred over the Lough Neagh basin and south Antrim (Synge and.
Stephens, 1966). In addition the distinctive Cushendun porphyry has a.
strong cone of distribution only north and north-west of its outcrop, and
no boulder clay of Scottish origin has been detected in the east-facing
glens of Antrim (detailed analyses of these drifts and the chronology of
the various ice-advances will be the subject of another paper).
It is known from the evidence of morainic accumulations between
Ballycastle, Ballymoney and Inishowen that Scottish ice was impinging
on the north coast of Antrim in the late stages of the Wûrm period
(Dwerryhouse, 1923). This has been called the Scottish Readvance to
north Antrim (Armoy moraine) (Charlesworth, 1939 ; Synge and Stephens,
i960). Charlesworth argued that this readvance of Scottish ice extended
southwards along the Antrim coast at least as far as Belfast Lough,
impounding pro-glacial lakes in the east-facing Antrim glens.
The
184
absence of Scottish till and the shoreline evidence directly contradicts
this hypothesis for the east coast of Antrim must have been free of Irish
ice at the time when L.G.i. was cut. There is no indication of any (Scottish)
ice advance post-dating this shoreline and thus destroying it south of
Fair Head. But shoreline L.G.i. cannot be traced along the coast west
of Fair Head and on Rathlin Island. This suggests that ice was present
north and west of Fair Head at the stage when the rest of the Antrim
coast was ice-free. Whether the ice north of the limiting Armoy moraine
(Fig. i) represents an actual readvance of Scottish ice, or was simply a
stage in the general decay of the last ice-sheets cannot be discussed further
here but it seems certain that shoreline L.G.2. can only have been cut after
the ice had disappeared completely from the coast west of Fair Head.
Thus two separate synchronous shorelines are involved and consequently
this limits the extent of this Scottish ice to an area north and west of
Fair Head. The deposits associated with shorelines L.G.I, and L.G.2.
do not contain a shell fauna and both are thought to be late-glacial in
age (Stephens 1963, 1966).
Shoreline Li is the highest shoreline in which shells (Littorina) are
found, and human artifacts have been recorded. Shoreline Li can be
regarded as the first post-glacial shoreline. Shoreline L2 developed
subsequent to Li and this also contains a shell fauna. However, it is
interesting that at Glenarm, Carnlough and Cushendall the crests of
certain shingle ridges rise some 10-15 ft above the notches of shoreline
Li. Moreover, it is not clear whether the gravels at Glenarm, of which
there are two series, both contain implements and shells. The 35 ft
(plus) shingle bar at Carnlough does not appear to contain shells. These
ridges cannot be late-glacial in age because of the absence of frostheaving and because they do not fall on the line of L.G.i. or L.G.2.,
but they may be remnants (together with some benches in till at Garrón,
Ardclinis and Tornamoney) of a pre-Littorina shoreline, perhaps of PreBoreal age (shoreline x in Fig. 3).
The presence of such high shingle ridges may be explained perhaps by
exceptional storm conditions during the formation of shoreline Li. But
as both Littorina shorelines (Li and L2) can be recognised as notches cut
at particular levels in superficial deposits, and as both contain a shell
fauna, it would appear that they are separate features from shoreline x.
The importance of determining the C-14 age of the peat below such one
of these high shingle bars (at Cushendall) can be stressed therefore, and
it will be interesting to compare this date with those obtained by Jardine
(1962, 1963, 1964) for sites in south-west Scotland. For the moment the
age and validity of a separate shoreline (x in Fig. 3) must remain in doubt.
On the other hand it is submitted that the field evidence supports the
185
interpretations made in this paper of the presence of remnants of two
late-glacial (L.G.I, and L.G.2.) and two post-glacial (Lr and Lz) shorelines
in north-east Ireland (see also Stephens, 1966, and Synge and Stephens,
1966).
REFERENCES
CHAPMAN, R.
1960 Glenarm : A geomorphological study of an
area on the Tertiary Basalts of Northern
Ireland. Undergraduate Dissertation, unpublished.
CHARLESWORTH, J. K.
1939 Some Observations on the Glaciation of
North-east Ireland. Proc. Roy. Irish Acad.
45, pp. 255-295.
COFFEY, G. andPRAEGER,R.LI.1904 The Antrim raised beach : a contribution
to the neolithic history of the North of
Ireland. Proc. Roy. Irish Acad., 25, pp.
145-200.
DWERRYHOUSE, A. E.
1923 The Glaciation of North-eastern Ireland.
Quart. Jour. Geol. Soc., 79, pp. 352-422.
HANNA, L.
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ACKNOWLEDGEMENTS
The author wishes to acknowledge the help received in the preparation of this
paper from F; M. Synge and N. Stephens. The work is part of a research programme
financed by a Northern Ireland Government Postgraduate Studentship during 1964
to 1966.
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