Clare County Development Plan 2023–2029 (as varied)

1. Page 491

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   Natural Heritage Sites in County Clare Site Name Sheet No. 1:50,000 Grid Ref. Principal Characteristics/Critical Feature(s)/Key Words Townland(s)/District Summary Description which has developed as a result of erosion by the sea. Caher Hill 52 R 5475 9065 Ordovician volcanics, graptolitic shales and cherts Caher Caher Hill is the type locality for the Caher Hill Formation. Yellow, cream and pinkcoloured amygdaloidal trachytes occur here. The yellow trachytes host enclaves up to 10cm in diameter of basic composition. The pink trachytes contain abundant orthoclase phenocrysts. The trachytes overlie a succession of black shales and cherts, basic lapilli tuffs and a sequence of basic tuffs, lavas and breccias. These rocks provide a record of sedimentation and volcanic eruptions within the contracting Iapetus Ocean. Graptolites found within the black shales have yielded a late Ordovician, Caradoc age for the rocks. The Caher Hill Formation is also exposed south and west of Lough Graney and near Lough Ea. Spillitic lavas occur at the latter locality.487

2. Page 492

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   Natural Heritage Sites in County Clare Site Name Sheet No. 1:50,000 Grid Ref. Principal Characteristics/Critical Feature(s)/Key Words Townland(s)/District Summary Description Carran Enclosed Depression 51 R 28 98 Ireland's largest enclosed depression Castletown, Ballyconry Ireland's largest enclosed depression. Large internally-draining basin with inlet springs and outlet via a swallow hole (or sink) developed within Carboniferous limestone. It is approximately 4.5km2 in area and 40m deep, implying a considerable length of time for development. The depression is divided into sub-enclosed basins and is ringed by moderate to steep slopes. The structure and hydrology of this depression resembles both an uvala (large and complex dolines) and a polje (closed depression in a karst area). Coad 51 R 2727 9141 Mushroom stones – isolated wave worn stones in grazing fields Coad The at least eight stones in question are an example of a phenomenon classed as mushroom stones. These are thought to have formed when lakes existed for periods long enough for water to dissolve the limestone below the lake level. Emergent limestone above the lake level was not dissolved. The stones at Coad comprise a large share of only about 63 mushroom stones known in the country as a whole.488

3. Page 493

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   Natural Heritage Sites in County Clare Site Name Sheet No. 1:50,000 Grid Ref. Principal Characteristics/Critical Feature(s)/Key Words Townland(s)/District Summary Description Coolagh River Cave 51 M 12400 01400 Dendritic Cave System with several stream sinks / swallow holes, Blind Valley, Active Uvala Ballynahown, Knockauns Mountain, Blakes Mountain, Cloghaun, Poulnagun The Coolagh River Cave is a mature cave system with many subterranean and subaerial karst features. It is a dendritic cave system with several stream sinks/swallow holes. The Coolagh River sink is at a karst window, at the end of a blind valley. The Coolagh River Valley, which continues southwards as a normally dry valley within the site, is also one of the major surface features of the Burren. County Council Quarry 51 R 150 995 Viséan Limestones and Namurian Shales. Ballyinsheen More Upper Viséan, Carboniferous limestones are exposed at this quarry. These wellbedded, dark grey limestones are rich in fossils. Fossils found at this site include crinoids, bryozoans and corals. These corals, in particular, the coral Orionastraea rete, correlate with specimens found outside Ireland and indicate a Brigantian age (uppermost stage of the Viséan) for these limestones. Basal Namurian Clare Shales overlay these Viséan limestones. Crossard 51 R 2688 9075 Mushroom rocks – isolated wave worn stone in grazing fields Crosard Mushroom stones are thought to have formed when lakes existed for periods long enough for water to dissolve the limestone below the lake level. Emergent limestone above the lake level was not dissolved. In some stones such as at489

4. Page 494

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   Natural Heritage Sites in County Clare Site Name Sheet No. 1:50,000 Grid Ref. Principal Characteristics/Critical Feature(s)/Key Words Townland(s)/District Summary Description Crossard, this has create d a marked bulbous mushroom shape develops with a cap on a pedestal. Doolin Cave 51 R 07485 96840 Dendritic cave system within Carboniferous Limestone Doolin Doolin Cave, a dendritic network of stream passages, is an active cave system, which has preserved various stages of cave development. Doolin Green Holes AKA: Hell Complex or Mermaid’s Hole 51 R 05600 97600 Karst caves in Carboniferous Limestone, inundated by postglacial seal level rise Doolin The Doolin Green Holes are the bestdocumented karst caves in Ireland and consist of a series of cave passages that formed at a lower sea level than today when the water was trapped in huge ice sheets. Since their formation the caves have been inundated by post-glacial sealevel rises and have preserved much evidence of this. Also of interest here are the photokarren and phytokarst. These erosional features, which are absent in the darkest parts of the cave, are the first of their kind to be recorded outside of the tropics.490

5. Page 495

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   Natural Heritage Sites in County Clare Site Name Sheet No. 1:50,000 Grid Ref. Principal Characteristics/Critical Feature(s)/Key Words Townland(s)/District Summary Description Doolin to Hags Head (Cliffs of Moher) 51, 57 From R106500 196000 to R101300 189200 Upper Carboniferous sedimentary rocks. Doonnagore, Luogh North, Luogh South, Lislorkan North, Slievenageeragh, Shingaunagh North etc A coastal section with a remarkable development of sand volcanoes in Carboniferous beds overlying slumped shales and sandstones. The ‘Fisherstreet Slide’ is a distinctive sheet, 30 metres thick, extending over some kilometres of the section. The entire sheet moved as a sedimentary slide, and now contains a wealth of soft sediment deformation features. It is part of the Gull Island Formation from Doolin southwards until the Central Clare Group and comprises the bulk of the cliffs from O’Brien’s Tower southward. The cliffs also illustrate cyclothems I and II (Tullig Cyclothem and Kilkee Cyclothem) of the five in the Central Clare Group. These cyclothems are repeated sequences of mudstone, siltstone and sandstone, formed by normal processes in the deltaic environment that created these rocks. They are normally separated by thin marine bands with distinctive goniatite fossils, allowing correlation of rocks and events across a wide area. They comprise a basin fill sequence with the greater depth and development of the basin in491

6. Page 496

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   Natural Heritage Sites in County Clare Site Name Sheet No. 1:50,000 Grid Ref. Principal Characteristics/Critical Feature(s)/Key Words Townland(s)/District Summary Description south west and central Clare. Accessible ledges of the sandstones also contain a wealth of trace fossils, apart from the very well known Liscannor Flags, which has the burrow Olivellites in abundance. The vertical sea cliffs in Upper Carboniferous shales and flagstones are of iconic status as a tourist attraction - this area is of considerable amenity value. Doonaha 63 Q889 531 Coastal exposures along approx. 3km of coastline. Namurian sandstones, siltstones and shales of the Gull Island Formation. Loop Head The succession comprises micaceous sandstones, siltstones and shales. Of importance at this site are the trace fossils preserved in the Upper Carboniferous, Namurian rocks. These starfish traces represent the only Namurian starfish traces in Ireland. The rocks are part of the Gull Island Formation, which includes the Fisherstreet Slide at its base. The presence of sand volcanoes at Doonaha indicates similar evidence of sedimentary instability. However, there are many other sedimentary and structural features of interest easily visible in the exposures. Elmvale 51 Elmvale 1: R 2590 9170 Mushroom rocks – isolated wave worn stones in grazing fields Elmvale Mushroom stones are thought to have formed when lakes existed for periods long enough for water to dissolve the492

7. Page 497

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   Natural Heritage Sites in County Clare Site Name Sheet No. 1:50,000 Grid Ref. Principal Characteristics/Critical Feature(s)/Key Words Townland(s)/District Summary Description Elmvale 2: R2587 9160 limestone below the lake level. Emergent limestone above the lake level was not dissolved. Fergus River Cave 51 R 252 923 Ancient cave with Carboniferous Limestone. Roughan The Fergus River Cave is one of the oldest known in Ireland, with calcite deposits dated at greater than 350,000 years old. It contains more than 3km of largely abandoned streamway which floods in very wet conditions. The water is derived in part from the sink in the Carran enclosed depression. The cave is an abandoned rising for the Fergus River, although it can flood in very wet conditions. It is notable also for mud stalagmites and for glacially derived sediments. Foohagh Point 63 Q 853 590 Growth fault within the Upper Carboniferous (Namurian) sandstone, siltstone and mudstone of the Central Clare Group Foohagh (to west side of Moore Bay, Kilkee) A spectacular growth fault can be seen in the cliff face at Foohagh Point. The growth fault at Foohagh Point displaces sandstones, siltstones and mudstones within the fourth cyclothem sequence of the Upper Carboniferous (Namurian) Central Clare Group. The pale coloured sandstones of this formation display clear thickening towards the fault.493

8. Page 498

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   Natural Heritage Sites in County Clare Site Name Sheet No. 1:50,000 Grid Ref. Principal Characteristics/Critical Feature(s)/Key Words Townland(s)/District Summary Description Glencurran Cave 51 R 2738 9633 An ancient cave system in the side of a wooded dry valley Poulaphuca Glencurran Cave is a truncated and largely sediment filled cave, making it potentially an older system than the postglacial origins of many Burren stream caves. It is a significant cave with a diversity of interest. It is largely earth-filled wide phreatic passage, with short sections of active stream cave. It has considerable geological and spelological potential as the most likely intersection to an undiscovered master cave between Castletown River Sinks in the Carran Enclosed Depression and the risings at Fergus River Cave. Gortlecka 51 R 3202 9499 Mushroom rocks – isolated wave worn stones in grazing fields Gortlecka The two stones in question are an example of a phenomenon classed as mushroom stones. These are thought to have formed when lakes existed for periods long enough for water to dissolve the limestone below the lake level. Emergent limestone above the lake level was not dissolved. In some stones such as at Gortlecka, this has created a marked smooth surface below a lip, whilst in more extreme cases a mushroom shape develops with a cap on a pedestal.494

9. Page 499

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   Natural Heritage Sites in County Clare Site Name Sheet No. 1:50,000 Grid Ref. Principal Characteristics/Critical Feature(s)/Key Words Townland(s)/District Summary Description Gull Island, Tullig Point and Trusklieve section 63 Q 770 515 to Q 800 550 Upper Carboniferous Namurian sandstones and siltstones Quilty, Oughterard, Tullig, Trusklieve The coastal section around Gull Island and Tullig Point displays some of the best sections in Clare of the Shannon Group and Central Clare Group sedimentary rocks which infilled the Clare Basin in the Namurian, and which now are the foundation of most of south west and central County Clare. It is the type section for the Gull Island Formation of the Shannon Group. The top of this Group is marked by the R1 marine band with goniatite fossil markers. There are an extensive range of sedimentary structures, and also tectonic structures, many of which were formed at the time of deposition and record the sediment instability on the basin slopes. There are slides, growth faults and slumps present. Key sections are at Gull Island to Tullig Point and at Illaunglass and Pouladav. Kilbreckan 58 R 399 761 Lead and silver-bearing mineral deposits in cherty Carboniferous limestone and dolomite Kilbreckan Td. Kilbreckan Mine was worked intermittently for silver and lead from 1834 until 1856. The mineralized bodies contain silver-bearing galena, pyrite, chalcopyrite, sphalerite and calamine in a calcite gangue. Other minerals include Bindheimite(a silver-bearing antimonite of495

10. Page 500

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    Natural Heritage Sites in County Clare Site Name Sheet No. 1:50,000 Grid Ref. Principal Characteristics/Critical Feature(s)/Key Words Townland(s)/District Summary Description lead), Bournonite (a sulphide mineral of copper, antimony and lead), Hemimorphite (a minor ore mineral of zinc), Quartz, Smithsonite (another zinc ore). In addition Kilbreckan is the type locality for the mineral ‘Kilbrickenite’ – now confirmed as the mineral Geocronite (a white sulphosalt mineral of lead). The main orebody, trending north-south, has a pipe-like shape and is up to 1m in width. A second, northwest trending mineralized body of similar thickness occurs also. Killinaboy 51 R 2711 9149 Mushroom rocks – isolated wave worn stones in grazing fields Killinaboy Mushroom stones are thought to have formed when lakes existed for periods long enough for water to dissolve the limestone below the lake level. Emergent limestone above the lake level was not dissolved. In some stones such as at Killinaboy, this has created a marked smooth surface below a lip.496

Source Clare County Council: Clare County Development Plan 2023–2029 (as varied) (2023–2029) · Licence the publisher's termsText read from the publisher’s PDF; tables, maps and drawings do not survive as text, and page numbers are the PDF’s (its first page is 1). Check the original before relying on a passage.