The Neolithic tomb reference article from the English Wikipedia on 24-Apr-2004
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Neolithic tomb

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Neolithic Tombs of Northwestern Europe, particularly Ireland, were built by the Neolithic (New Stone Age) people in the period 4000 - 2000 BC. There are four main types:

All these types of tomb were built from large slabs of [[Rock (geology) | rock]] which were uncut or worked only slightly. In each case, there was a 'doorway' made from two large stones facing each other. The doorway led to an inner chamber, or a passage and chamber, lined with flat slabs. In all but the Portal Dolmens, the tomb was then covered in earth and small stones to make a mound.