Coney Island
Coney Island is the largest and the most famous of the three islands off the northern coast of the Coolera peninsula. It lies in Sligo Bay between Rosses Point and Ben Bulben in the north, and Strandhill and Knocknarea to the south. The island which is 2.25km long by 1 km across is accessible by boat from the pier at Rosses Point, but the most popular route is by way of the tidal causeway at Cummeen Strand when the tide is out. This strand is exposed at low tide and is marked by 14 stone pillars for a distance of 2.5km leading to the island.
This is the original Coney Island (though not uniquely named in Ireland) which gave its name to the American Coney Island. In Irish the name means “the island of rabbits”. In the 19th century the merchant ship “Arethusa” used to sail between Sligo and New York. The captain of the ship, observing many rabbits in the New York Island, named it after his own Coney Island in Sligo Bay. Or so the story goes…
Access to Coney island via Cummeen Strand is poorly signposted. A waypoint is provided below for the turn-off the main road. Driving from Strandhill take the main Sligo road for 2km. Once you pass Scarden graveyard on your left, it is the next left-hand turn. If you don't wish to douse your car in saltwater, it is quite possible - and indeed very enjoyable - to walk the 2.5km causeway; please consider the returning tide and your own fitness level before attempting to walk!
The strand is entirely submerged at high tide. You undertake this journey at your own risk!
Click here for tidal information.
After you return - don't forget to wash your car to remove the salt!
Irish Limestone
Around 60% of Ireland is underlain by limestone and with only a small few exceptions, Irish limestone belongs to two periods: the Carboniferous (340-300 million years go) and the Cretaceous (120-70 million years ago.
Carboniferous limestones are typically hard and its colour ranges from black to pale grey in colour; it is found in almost every part of Ireland, except Co. Antrim and Co. Wicklow. The hard nature of the carboniferous limestone makes it ideal for use in building stone.
Cretaceous limestone, typically chalk, is a good deal softer and usually whitish in colour; in Ireland it is predominantly found in Counties Antrim, Armagh, Down, Derry & Tyrone. Cretaceous limestone is too soft to be used in building, but is often used in cement-making.
Limestones are predominantly or entirely composed of calcite. Some limestones are almost pure carbonate; others contain significant proportions of other material – most commonly sand, clay (mud or shale) and chert (very fine grained silica). The non-carbonate material may be distributed throughout the rock, may occur as small nodules (especially of chert) or may be concentrated in distinct beds (most commonly, beds of shale) inter-bedded with the limestone. The limestone may also contain small amounts of metallic minerals such as pyrite, marcasite, or galena, and in some places these may be concentrated in distinct veins or masses; where these mineral deposits are sufficiently large and concentrated to be exploited economically, they are termed orebodies, as found at Tara Mines, Navan, Galmoy, Co. Kilkenny and Lisheen, Co. Tipperary.
Limestone is formed in various different ways and in different geological situations, normally in the sea. It may be deposited in deep water far from land, in shallow water near the shore, or anywhere in between. Many limestones are predominantly composed of the calcareous shells or skeletons of marine organisms, such as coral, but others are formed chemically by precipitation of carbonate from shallow waters. Some form in extensive horizontal layers (beds) which may be as thin as a few millimetres or as thick as several metres. Others form as massive unbedded banks or mounds of fine-grained calcareous debris (mud mounds), which can be many metres thick in the centre, thinning out towards the edges.
Fossils on Coney Island
The cache site is on a plateau of limestone at the edge of the sea; this cache is most easily attempted at low tide. Please be careful not to slip on the wet rock. The limestone here can be categorised as Fossiliferous Limestone, as you can see it contains a rich abundance of fossils. Fossils are the remains of prehistoric organisms preserved in petrified form or as a mould or cast in rock.
Two distinct fossil types are visible at the cache site.
One is rather small and spotty in nature.
The second is rather larger and present both head-on and in cross section.
To log this Earthcache
Please send me answers to the below questions via my profile. Some at-home research will be required, in addition to your visit to the earthcache site.
- Is limestone a sedimentary, metamorphic or igneous rock?
- On the basis of the information provided above, in what period was the limestone at the cache site formed?
- What evidence brought you to this conclusion?
- Describe the visual appearance of the two type of fossils you can see here. Please measure both types providing your measurements in mm. For the larger type, please provide the diameter of the circular appearance.
- Please name at least one type.
- The cache site is on plateaued limestone, below the level of the path. There is a drop down - how far down is it?
- OPTIONAL: feel free to upload pictures from your visit, but please do not include pictures of the fossils!
You may find these two information sheets helpful in idetifying the fossil types:
http://www.burrengeopark.ie/wp-content/uploads/2013/04/fossils_in_the_limestone1.pdf
http://www.geoneed.org/wp-content/uploads/downloads/2011/05/Module-B4-Information-Sheets.pdf
http://geoschol.com/counties/SLIGO_GEOLOGY.pdf
Do not wait to log your find. As soon as you have emailed me the answers via my profile, please log the cache. I will contact you if there are any issues with your answers.
Sources:
www.gsi.ie
www.wikipedia.com
www.gostrandhill.com
Leave No Trace
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The cache has been placed in accordance with the "Leave No Trace" principles. Please respect these principles when inspecting the earthcache site. Under no circumstances should you attempt to remove fossils from the rock faces.
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