Eskers: did they run over or under the ice?

I HAVE a particular interest in eskers because I live on one. Most people know what they are — ridges of sand and gravel snaking across the countryside looking a bit like derelict railway embankments.

Their track often bears no relationship to the contours of the land they cross and, in their natural state, they carry a distinctive vegetation type known as esker woodland.

The word esker is one of the few Irish language words to be adopted into English. Irish “eiscir” means a ridge surrounded by flat land. Our most famous one is the Eiscir Riada that crosses the middle of the country from east to west, meeting the Shannon at Clonmacnoise.