The Portencorkrie Complex of Wigtownshire

1943 ◽  
Vol 80 (5) ◽  
pp. 171-195 ◽  
Author(s):  
Norman Holgate
Keyword(s):  
Geological Survey ◽  
Irish Sea ◽  
Ordnance Survey ◽  
Igneous Complex ◽  
North West ◽  
The North ◽  
Plutonic Rocks ◽  
The Irish Sea ◽  
North And South

The Portencorkrie igneous complex, a trapezoidal area of plutonic rocks intrusive into Silurian sediments, is situated in the Rhinns district of Wigtownshire some sixteen miles south of Stranraer and about four miles north-west of the Mull of Galloway. It appears on the Geological Survey (Scotland) 1-inch Sheet 1, and lies within the Ordnance Survey 6-inch quarter-sheets Wigtownshire 33 S.W. and 37 N.W. To the north and south the igneous margin can be followed with fair accuracy, while to the east the boundary is obscured by drift. Westwards, the rocks pass beneath the Irish Sea.

XI.—The Glaciation of Holyhead Mountain

1904 ◽  
Vol 1 (10) ◽  
pp. 504-505
Author(s):  
Edward Greenly
Keyword(s):  
Irish Sea ◽  
General Level ◽  
The South ◽  
The West ◽  
Scottish Highlands ◽  
The North ◽  
The Irish Sea ◽  
North And South ◽  
Sea Cliffs

The bare and rocky hill known as Holyhead Mountain is of considerable interest in connection with recent geological events, standing as it does some thirty miles out from the highlands of Carnarvonshire into the Irish Sea Basin; and in such remarkable isolation, for it is much the highest of the five hills which rise above the general level of the platform of Anglesey.Its height is only 721 feet, but so strongly featured is it, especially towards the west, that one feels the term ‘mountain’ to be no misnomer, and can hardly believe it to be really lower than many of our smooth wolds and downs of Oolite and Chalk. Being composed, moreover, of white quartzite (or more properly of quartzite-schist), and being so bare of vegetation, it recalls much more vividly certain types of scenery in the Scottish Highlands than anything in those Welsh mountains that one sees from its sides. Towards the east it slopes at a moderate angle, but a little west of the summit it is traversed by a very strong feature, due to a fault, running nearly north and south, along which is a line of great crags, facing west, and prolonged northwards into the still greater sea cliffs towards the North Stack. Beyond this the land still remains high, but is smoother in outline, a somewhat softer series of rocks extending from the fault to the South Stack, where the high moors end off in great cliffs above the sea.

V.—Note on two Cephalopods Obtained by Lieut.-Col. Skinner, R.A.M.C., from the Valley of the Tochi River on the North-West Frontier of India

1904 ◽  
Vol 1 (10) ◽  
pp. 490-493
Author(s):  
G. C. Crick
Keyword(s):  
British Empire ◽  
Geological Survey ◽  
The West ◽  
Lower Eocene ◽  
North West ◽  
The Core ◽  
Fossil Remains ◽  
The North ◽  
North And South ◽  
Upper Mesozoic

The valley of the Tochi River is an outlying corner of the British Empire in India forming a portion of Waziristan, the boundary of which was delineated in 1894–5 by an Anglo-Afghan Commission from the Afghan provinces of Khost on the north and Birmul on the west. Mr. F. H. Smith, of the Geological Survey of India, accompanied this Commission as geologist, and his observations “On the Geology of the Tochi Valley” were published in 1895 in the “Records of the Geological Survey of India” (vol. xxxviii, pt. 3, pp. 106–110, pl. iii). On p. 109 he says:—“The range of hills between Idak and Mirán Shah is formed by an anticlinal ridge which approximately strikes north and south, and which is composed of these lower eocene beds. In the core of the anticlinal a considerable thickness of massive dark grey limestone is exposed, in which I could find no fossil remains; the age of this limestone is therefore doubtful, and there is no evidence of any kind to show whether it belongs to the lowest tertiary or upper mesozoic age.”

The Spread of Elminius Modestus Darwin In North-West Europe

1958 ◽  
Vol 37 (2) ◽  
pp. 483-520 ◽  
Author(s):  
D. J. Crisp
Keyword(s):  
East Coast ◽  
Irish Sea ◽  
North Coast ◽  
Long Distance ◽  
North West ◽  
The North ◽  
Competition For Space ◽  
South East England ◽  
The Irish Sea ◽  
Balanus Balanoides

Material collected prior to 1940 indicates that Elminius modestus was not present on British coasts at that time.Elminius increased in abundance in south-east England from 1946 to 1950 and extended its range as far as the Humber, where it halted.Its advance westwards along the south coast was similarly halted at Portland, but by 1948 independent colonies had been established in several of the river systems of Devon and Cornwall, in Milford Haven, and in the Bristol Channel.The first populations in the Irish Sea were in Morecambe Bay. From there Elminius spread rapidly south and west along the north coast of Wales, and more slowly north and west towards Galloway, eventually bridging the sea to the Isle of Man.Detailed observations showed that Elminius advanced along the uniformly favourable north coast of Wales as a definite front moving at a rate of approximately 20–30 km per year. Around Anglesey where tidal currents were stronger it appeared simultaneously in many scattered centres.A distinction is drawn between marginal dispersal taking place under the influence of normal agencies at the boundary of an existing population, and remote dispersal due to an artificial or freak transport over a long distance. In the case of Elminius the maximum distance that is likely to be bridged by marginal dispersal in the absence of strong residual drifts is about 30 miles.Elminius probably first appeared near Southampton, and was introduced into the Thames estuary area probably by remote dispersal. Thence it spread along the east coast and was transported to Holland. Its extension into south Devon, the Bristol Channel, the Irish Sea, and to the French coast must also be attributed to remote dispersal.The main ecological effects of Elminius result from competition for space with Balanus balanoides. Since Elminius breeds in summer, its dominance has a profound effect on the composition of the summer plankton, greatly increasing the number of barnacle nauplii, presumably at the expense of other larvae.

Small-scale variation within a Modiolus modiolus (Mollusca: Bivalvia) reef in the Irish Sea. II. Epifauna recorded by divers and cameras

2008 ◽  
Vol 88 (1) ◽  
pp. 143-149 ◽  
Author(s):  
W.G. Sanderson ◽  
R.H.F. Holt ◽  
L. Kay ◽  
K. Ramsay ◽  
J. Perrins ◽  
...  
Keyword(s):  
Irish Sea ◽  
Small Scale ◽  
Competitive Response ◽  
North West ◽  
The North ◽  
Strangford Lough ◽  
Modiolus Modiolus ◽  
Bed Form ◽  
The Irish Sea ◽  
Horse Mussel

The spatial heterogeneity of epifauna on a Modiolus modiolus reef off north-west Wales was investigated using divers. The community associated with these horse mussels was similar to that described previously from Loch Creran and the north basin of Strangford Lough. Some differences in epifauna may be attributable to the less sheltered nature of the site. Modiolus modiolus numbers and the associated epifaunal community were significantly different between ridge and trough sub-habitats. Troughs can be considered ‘reduced’ ridge communities whereas ridges have high densities of horse mussels and certain sessile taxa were correlated with their abundance. Modiolus modiolus aggregation as a competitive response to the feeding environment, enhanced food availability on ridges and sediment deposition amongst mussel clumps may start to explain the undulating bed-form. Patchiness in community composition and periodic cover by ophuroids has implications when considering the monitoring of the horse mussel community. Stratified, in situ recording of the highly populated ridges could improve the statistical sensitivity of monitoring horse mussel reefs whilst simultaneously focusing on the more sensitive indicators of fishing threats.

scholarly journals Towards Winter Seasonal Predictability of the North West European Shelf Seas

2021 ◽  
Vol 8 ◽  
Author(s):  
Jonathan Tinker ◽  
Leon Hermanson
Keyword(s):  
North Sea ◽  
Irish Sea ◽  
Seasonal Forecasts ◽  
North West ◽  
Southern North Sea ◽  
The North ◽  
Predictive Skill ◽  
European Shelf ◽  
Shelf Seas ◽  
The Irish Sea

We investigate the winter predictability of the North West European shelf seas (NWS), using the Met Office seasonal forecasting system GloSea5 and the Copernicus NWS reanalysis. We assess GloSea5’s representation of NWS climatological winter and its skill at forecasting winter conditions on the NWS. We quantify NWS winter persistence and compare this to the forecast skill. GloSea5 simulates the winter climatology adequately. We find important errors in the residual circulation (particularly in the Irish Sea) that introduce temperature and salinity biases in the Irish Sea, English Channel, and southern North Sea. The GloSea5 winter skill is significant for SST across most of the NWS but is lower in the southern North Sea. Salinity skill is not significant in the regions affected by the circulation errors. There is considerable NWS winter temperature and salinity persistence. GloSea5 exhibits significant predictive skill above this over ∼20% of the NWS, but for most of the NWS this is not the case. Dynamical downscaling is one method to improve the GloSea5 simulation of the NWS and its circulation, which may reduce biases and increase predictive skill. We investigate this approach with a pair of case studies, comparing the winters of 2010/2011 and 2011/2012 (with contrasting temperature and salinity anomalies, and NAO state). While 2 years are insufficient to assess skill, the differences in the simulations are evaluated, and their implications for the NWS winter predictability are considered. The NWS circulation is improved (where it was poor in the GloSea5), allowing more realistic advective pathways for salinity (and temperature) and enhancing their climatological spatial distributions. However, as the GloSea5 SST anomaly is already well simulated, downscaling does not substantially improve this – in other seasons or for other variables, downscaling may add more value. We show that persistence of early winter values provides some predictive skill for the NWS winter SST, and that the GloSea5 system adds modestly to this skill in certain regions. Such information will allow prospective end-users to consider how seasonal forecasts might be useful for their sector, providing the foundation on which marine environmental seasonal forecasts service and community may be developed for the NWS.

Structural Features of the Alston Block

1933 ◽  
Vol 70 (6) ◽  
pp. 241-254 ◽  
Author(s):  
K. C. Dunham
Keyword(s):  
Structural Features ◽  
Geological Survey ◽  
North West ◽  
Northern Area ◽  
The North ◽  
Tectonic History ◽  
Fault Block ◽  
History Of ◽  
The Cross ◽  
North And South

The Northumbrian Fault-block, forming the central part of the Pennine Chain, is a region of gently tilted Carboniferous sediments, bounded on the north, west, and south by major faultlines. It is divided naturally into two structurally complementary areas, symmetrically disposed to the north and south of the syncline of Stainmore. The present paper is concerned exclusively with the northern area, named by F. M. Trotter and S. E. Hollingworth the “Alston Block” (1928) and by H. G. A. Hickling the “Cross Fell Block” (1930). The first-named authors, who have recently completed a revision of the Geological Survey sheet covering the north-west corner of the block, have discussed in detail the structure of that district and have described the broad outlines of the tectonic history of the block (1928, 1932).

Report of experiments made on the tides in the Irish Sea; on the similarity of the tidal phenomena of the Irish and English Chan­nels; and on the importance of extending the experiments round the land’s-end and up the English Channel. Embodied in a letter to the hydrographer, by Captain F. W. Beechey, R. N., F. R. S.. Communicated by G. B. Airy, Esq., F. R. S., Astronomer Royal

1851 ◽  
Vol 5 ◽  
pp. 743-746
Keyword(s):  
High Water ◽  
The Other ◽  
Irish Sea ◽  
English Channel ◽  
The North ◽  
The Irish Sea ◽  
The Times ◽  
North And South ◽  
Different Parts

The author commences by stating, that the set of the tides in the Irish Sea had always been misunderstood, owing to the disposition to associate the turn of the stream with the rise and fall of the water on the shore. This misapprehension, in a channel varying so much in its times of high water, could not fail to produce much mischief; and to this cause may be ascribed, in all probability, a large proportion of the wrecks in Caernarvon Bay. The present inquiry has dispelled these errors, and has furnished science with some new and interesting facts. It has shown that, notwithstanding the variety of times of high water, the turn of the stream throughout the north and south Channels occurs at the same hour, and that this time happens to coincide with the times of high and low water at Moricombe Bay, a place remarkable as being the spot where the streams coming round the opposite extremities of Ireland finally unite. These experiments, taken in connexion with those of the Ordnance made at the suggestion of Professor Airy, show that there are two spots in the Irish Sea, in one of which the stream runs with considerable rapidity, without there being any rise or fall of the water, and in the other the water rises and falls without having any perceptible stream; that the same stream makes high and low water in different parts of the channel at the same time; and that during certain portions of the tide, the stream, opposing the wave, runs up an ascent of one foot in three miles, with a velocity of three miles an hour.

The occurrence of Norway lobster (Nephrops norvegicus) larvae off the Portuguese coast

2005 ◽  
Vol 85 (4) ◽  
pp. 937-941 ◽  
Author(s):  
Antonina dos Santos ◽  
Álvaro Peliz
Keyword(s):  
Production Method ◽  
Irish Sea ◽  
Biomass Estimation ◽  
Nephrops Norvegicus ◽  
North West ◽  
Portuguese Coast ◽  
The North ◽  
Norway Lobster ◽  
South West Coast ◽  
The Irish Sea

Norway lobster (Nephrops norvegicus) larvae have been investigated in northern European waters, particularly in the Irish Sea where biomass estimation studies are used for the annual larval production method. However, nothing is known of their distribution in southern European waters, off the Portuguese coast or in the Mediterranean Sea. From zooplankton sampling off the Portuguese coast between October 1986 and March 2001, planktonic larvae of this species were known to occur from January to April off the north-west and south coasts. In the north, larvae were only observed over the shelf, shoreward of the upper limit of the adults' distribution. Larvae were never collected off the south-west coast of Portugal, even though this is one of the largest fishing grounds for this species off the Iberian Peninsula. The absence of larvae from all surveys in this region may relate to the local oceanographic conditions and shelf width.

V.—Glacial Geology: Old and New

1892 ◽  
Vol 9 (7) ◽  
pp. 310-321
Author(s):  
T. Mellard
Keyword(s):  
West Coast ◽  
East Coast ◽  
Irish Sea ◽  
Glacial Geology ◽  
The South ◽  
North West ◽  
The North ◽  
The Subject ◽  
The Irish Sea ◽  
River Valleys

Over twenty years ago I commenced the study of the glacial deposits of the neighbourhood of Liverpool, and as the observations grew they came to embrace a considerable share of the drainagebasin of the Irish Sea.I have personally inspected and kept full records of all of the important artificial excavations likely to throw light upon the subject, in addition to examining and making sections of the natural exposures of glacial drift which abound on the north-west coast of England, the coast of Wales, and in the river valleys draining into the Irish Sea, and to a lesser extent the drift on the east-coast of Ireland and the south of Scotland.

Excavations at Caerau Ancient Village, Clynnog, Caernarvonshire, 1933 and 1934

1936 ◽  
Vol 16 (3) ◽  
pp. 295-320 ◽  
Author(s):  
B. H. St. J. O'Neil
Keyword(s):  
Large Area ◽  
Mountain Slope ◽  
Ordnance Survey ◽  
North West ◽  
The Road ◽  
The North ◽  
Excellent Preservation ◽  
A Site ◽  
North And South ◽  
Agricultural Settlement

Mynydd Craig-goch, the westernmost height of a rocky ridge of the Snowdon mountains, slopes gently down to a watershed at the head of the Afon Dwyfach, over which run the railway and the main road from Criccieth and Portmadoc to Caernarvon. Between the ninth and tenth milestones from Caernarvon, immediately to the east of the road and thus on the lowest part of the mountain slope, there lie the remains of a most extensive primitive agricultural settlement. It is not marked on the Ordnance Survey map (6 in. 26 NE.), but was known locally, and the farm within which most of it lies bears the significant name Caerau. Its recognition as a site of great possibilities on account of its excellent state of preservation is due to Mr. W. J. Hemp, F.S.A. The settlement must originally have extended north and south for a distance of about half a mile. It may, indeed, have been contiguous with other settlements on the north and north-west, thus forming part of a large area of cultivated land, since there exists in excellent preservation a house or hut-group of the same type with at least one typical field about one mile to the west on the farm of Cefn Graianog. This point, however, cannot now be determined on account of more recent agricultural developments around the farm of Bodychain.

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