The cairns at Loughcrew are aligned to the rising sun at the equinoxes. The sun shines through the passage and illuminates the carvings on the back wall, progressing from left to right. CC BY-SA Rob Hurson via flickr, wandermondo.
The website Carrowkeel.com has detailed information:
Within this ancient corbelled room you are presented with the classic cruciform chamber of an Irish Passage Cairn. This is among the oldest free-standing buildings in the world and may date from as early as 3,500 BC. There are many small engravings on the chamber stones, in particular the west sill. Three small cells, seperated from the central space by sillstones open off the main chamber, to the south, west and north. The backstone of the west recess is richly carved with symbols which resemble combs and flowers. This is the Sliabh na Caillí Equinox Stone.
Now let’s compare these petroglyphs with other from elsewhere, and some of the Peratt instabilities.
