Cliffs of Moher

© photo : Mathieu Morverand

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The Burren limestones were laid down at the end of the Lower Carboniferous period. For millions of years afterwards sand and mud were washed on top of them and these sediments formed shale and flagstones, which can be best seen at the cliffs of Moher, where they plunge 700 feet to the sea and extend for five miles.