Ceis Mountain, Co. Sligo, is near where we now live. We have explored the Habitats and Wildlife of Lough Allen for
about 10 years. Now new places and interesting plants and wildlife beckon. Ceis is an free-standing mountain but
associated with the Bricklieves and some 20km. northwest of the Curlew Mountains. It is famous for its string of
small caves on its south flank and the interesting animal and human associations with them in the past.
It is part of a cluster of hills in the area which are topped by neolithic cairns reflecting the occupation and the start
of working this land c. 4,000 BC. This human intervention in the landscape is fascinating — not an area of our
expertise — but it does provide an interesting landscape, an exciting sense of oneness with unknown ancestors,
and new features which can become habitats for the wildlife and plants of the uplands. Many of the images shown
here come from an early exploration by us as we, too, moved into the area!
Particular features of the geology do control life that occurs there; the altitude, amount of rain/sunshine, the
alkalinity of the underlying rock and glacial changes made to the countryside during the period of the Ice Ages.
The recent and ancient history and archaeology is beautifully covered in a Voices from the Dawn article which
you can find HERE.
‘Beau’
Slieve League, Co. Donegal
These are gentle mountains nowadays but both the cairn and caves provide impressive views out over the plain,
obviously acting as an attraction and a refuge for the first settlers. Some of the water channels through the rock
are impressive and seem puzzling in the context of being halfway up the hill and close to a rounded summit with
no large source of water. But, of course, these channels would have been formed when Ceis was part of a much
larger area of raised largely flat bedded uplands. Their drainage systems would formerly have coped with major
water movements and what we see now are only the dry remnants of a larger overall underground water system.
This landscape might have been a raised plateau with the hills and valleys we now know having been created by
the action of glaciers in comparatively recent times. Likewise, the small lakes on the eastern side of Ceis, Lough
Labe and Lough Gowra lie in a deep glen presumably carved out by recent glaciers.
So what are the Rocks?
Ceis Corran is limestone country of horizontally bedded Upper and Lower Bricklieve Formation, just as is found on
the Bricklieve Mountains with their similar and numerous prehistoric cairns to the east. All these cairns are in
clear sight of one another and all top their particular ridge or summit. Our ancestors would have been in visual
contact with one another? Perhaps this placement of the cairns reflects the natural flatness of the underlying rock
dipping by only 5º to the south east. It was easy to work on the summits! The bedding at the caves, lower down, is
large and substantial with dense solid limestone. The Upper Bricklieve, as seen from the rocks collected for
building the cairn in the image above, is more porous and fractured and prone to crumbling and breaking up. This
seems the nature of the formation rather than any recent erosion or frost damage.
Perhaps this fundamental nature of the rock appealed to early settlers? It provided ready building materials with
which to build landmarks and burial features high above where they lived and farmed. The Geological Maps do
not differentiate much between the BKU and BKL strata (Bricklieve Upper and Lower); they just lie on top of one
another. But when you compare strata from the top of Ceis Corráin and the Bricklieve mountains with the strata
from the Caves of Ceis, they are physically quite different. One is solid and hard to extract, the other is porous,
brittle and available as light portable stones all over the high ground. The caves are at a lower altitude. The Upper
Bricklieve Formation is not widely visible on Ceis now but there still was enough for people to build the fine and
large Cairn photographed above.
All Cairns in this south Sligo region are on the
northerly flanks of the upland ridges. These are
the highest points on most ridges as the topo-
graphy seems to follow the geology which
consistently dips gently towards the south.
Altitude of Cairns:
Site
Altitude at Cairn
Dipº
Kesh
350
5 SE
Trean MacMurtagh
240
3 SE
Treanscrabbagh
280
10 S
Carrowkeel
300
5 S
Carricknahorna
300
5 S
(highest of 3 cairns)
Doonaveera
280
5 SSW
The Carrowkeel plateau in particular is very flat
limestone with steep valleys between some of the
cairns. The locations listed above are moving east
from Ceis and are from 880m to 1500m. apart
except at Carrowkeel where they are within
shouting distance of one another!
We tend to associate limestone with lowlands, e.g. the central plain of Ireland. But in certain places this limestone has been uplifted and invariably provides an attractive habitat for plants. For example, the Burren in
Clare. The Burren is well known for its karst landscape where the underlying rocks are exposed over a large area and specific plant species are adapted to growing in sheltered cracks and crevices. The north west of
Ireland, also, has many high limestone regions such as Ben Bulben (Co. Sligo) and its adjoining mountains and steep glens. Similarly the lesser known ‘Burren’ near Blacklion in Cavan. There is also a small area of
exposed limestone pavement outside Manorhamilton in Co. Leitrim.
The limestone uplands of the Ceis and Bricklieve mountains are, on the other hand, largely covered. On Ceis the lower slopes are mainly shallow but rich grassland with many stunted trees, typically thorn, Hazel and other scrub. The
higher ground is in parts grazed but other areas have gone back to a typical acidic plant coverage dominated by very dense and high heathers. This is probably based on a thin soil or glacially derived till combined with a very wet
exposed climate leading to patchy blanket bog formation. Also, interestingly there is a small raised bog associated with Lough Labe which looks like an interesting botanical location. A short distance to the south is the turlough lake
of Lough Gowra where the unusual Fen Violet is to be found. [More later, we hope!]
This mixture of a limestone base and a possibly acidic skim of soil on the surface has led to an interesting Flora. Nowhere is the rock deeply buried. It is exposed at the caves and, as indicated by all the cairns, it is readily available
either as broken stones (Upper Bricklieve type) or the more consolidated cherty bedding as in the caves, There are a good variety of Orchids on this mountain, often with a small patchy distribution but some significant clusters on
the warmer grassier southern slopes. Most orchids are lime loving plants. Some of these species are nationally important and some are common enough but nice to see as a grouping. Interestingly many of these species seem to
thrive in cohabitation with hillside farming, particularly one very rare species. This is a pattern of coexistence that has probably existed for many years. The hilly and rocky terrain has prevented the land from being disturbed and light
and late grazing has in several areas provided ideal habitats for a variety of wild plants. This is beneficial to the biodiversity of the area and possibly the plants also benefit farming in highlighting a stable ecosystem which may not
have changed for generations and which can qualify such land for biodiversity and conservation support.
The Greater Butterfly Orchid. Plantathera chloranta
A stunning and somewhat elusive orchid which grows here in large numbers on the grasslands on base rich soil. These conditions along with warm sunshine allow this plant to thrive with specimens up to 50cm in height. The greenish white flowers, twisted flower stalk and very long thin slightly curving spur at the back of the flower, are characteristic for this species. (The Lesser Butterfly Orchid, Plantathera bifolia, was also present but mainly in wetter, rushier boundary areas of less grazed fields.)Bricklieve Formation.
Another image showing this solid thick bedded rock with horizontal bedding at the western slopes of Ceis Corrán where the caves are formed. The vertical cliff and the caves would be typical of this formation. And their location here, halfway up the hill, may indicate the boundary between this rock classification and the higher strata of the Upper Bricklieve Formation that is found near the cairns.Montane Vegetation.
Even in Ireland, where most of our mountains are not very high, plant species do vary as you climb upwards. Here are four attractive specialists from Ceis Mountain. Some of these grow directly from gaps in exposed rock or in the richer limestone fields below the summit. LEFT: Wild Thyme (Thymus polytrichuis) A common aromatic perennial creeping and woody under-shrub of dry limey places. It stood out here as the cairn was possibly the most suitable habitat available. TOP LEFT… Hairy Rock Cress (Arabis hirsuta) Another exposed limestone plant typical of the cairn habitat of Ceis Corran. Quite a sizable plant with lanceolate leaves and small white cruciform flowers with prominent styles. Apologies for a constrained photo; this was a tallish plant in rather exposed conditions! TOP RIGHT: Great Wood-rush (Luzula sylvatica) is common in certain oakwoods and in cleared mountain tops where it hangs on as a relict long after the woodland has been cleared. It is a very common plant in Oak woodlands based on acid soils (Quercus petraea woods) where the wonderful Bilberry (or Fraughan) also grow and are harvested by local communities. Both these species often survive on bare mountains. This acidic Oakwood is called a Blechno-Quercetum based on the dominant species (Q. petraea) and these associated species. The presence of associated plants seems to imply that an acidic environment persisted here even on these totally limestone peaks! BELOW: The truly delightful, often missed, Frog Orchid (Coeloglussum viride). This can vary in colour but the typical pink green and purple hues are shown in this specimen — one of a group of about 20 plants found halfway up Ceis on its northern flanks. Not a rare species it can, however, be difficult to find outside of its ‘special’ areas. A plant of limestone hills and always very special to see especially when freshly flowering… and when one white flowering specimen was found!
ABOVE: Brittle Bladder Fern (Cystopteris fragilis) Typically found on limestone rocks and stone walls in the West of Ireland.
BELOW: Burnet Rose (Rosa spinosissima) Likes limestone pavements and calcareous dunes. Has white to pink flowers.
Two beautiful Orchids… one common, one rare and very local…
Heath Spotted Orchid Dactylorhiza maculata
This is a common species very similar to the Common Spotted Orchid (Dactylorhiza fuchsii). That species is lime loving and grows in abundance on roadsides and in quarries. The Heath Spotted is acid loving. Only this single solitary plant was found in grass very close to the base of the cairn. The Heath Spotted Orchid is identified by having a large undivided lower lip on the flower. There is a small tooth in this but it is very different from the Common Spotted Orchid which has a lower lip divided into 3 lobes. There were Common Spotted Orchids on the lower slopes of the mountain so this brings to 6 the number of different species recorded on the mountain. Again apologies for a not perfect picture. This specimen was shaking in the steady breeze that was blowing over this cairn. However we have included it to show the variety of orchids adapted to this specific habitat. The mixture of acid soil on a base substrate, perhaps, enhancing this diversity?Small White Orchid Pseudorchis albida
This was an exciting find. It was found in a cluster of 3 beside a sheep path on the southern flanks of Ceis in among a field of Greater Butterfly Orchids. It was a stunning surprise to find these in this area where they have not been recorded and where they were very exposed both to weather and grazing. We have actively studied this plant over recent years. It has several well known locations in north Cavan in the foothills of The Playbank. It is an adaptable species and a hard one to find being probably more common and widespread than realised. On that basis it was spontaneously found recently in Leitrim near Manorhamilton by the age-old scientific technique of looking over a gate! This species flowers in late May or early June and these specimens were encountered at the start of July. Hence the stature of the plants, large by Small White standards, and the fact that most of the flowers had withered back. This site was at an altitude of 210m. whereas the site in Cavan has Small White Orchids flowering between 140m and 165m. Perhaps the higher altitude at Ceis led to later flowering? Also, despite considerable searching, only 3 of these orchids were found (20+ in 2017) at the Co. Sligo site, so conditions may not have been ideal?
Home Habitats Curious Plants Wildlife Ecology The BLOG Contact Us
An exploration of wild & interesting places in Ireland and their western European/American flora and fauna…
BELOW: A parting view looking over the side of the cairn towards Castlebaldwin and L. Arrow. This shows the
Thyme and the Burnet Roses and the Great Wood-rush in among the the tumbled Bricklieve limestone blocks,
One wonders the way this place has changed in the past 5,000 years since these cairns were built, or the 20,000 years since ice
formed these mountains, or the 300 million years since these rocks were laid down?
Bedded Limestone
Fractured top bed.
Ground up limestone till
Thin bed of turf
Acid loving plants… Heather
Maidenhair Spleenwort. Asplenium trichomanes
The common Spleenwort of the west. Another wall or limestone loving fern.
Alternatively known as Kesh, Keshcorraun, Keash… Ceis is a ‘wattled causeway’ and
Corrán is a ‘hook, crescent, jawbone’ and also refers to the fern, Spleenwort?
