chamber 13 feet by 15 with an immense cover-slab nearly 20 feet in
length: the whole was covered with a mound of earth. The chamber
contained human bones and "lanceheads of stone and bronze." A famous
tomb of a similar type exists at Marcella in Algarve. The chamber is a
fine circle of upright slabs. It is paved with stones, and part of its
area is divided into two or perhaps three rectangular compartments. A
couple of orthostatic slabs form a sort of neck joining the circle to
the passage, which narrows as it leads away from the circle, and was
probably divided into two sections by a doorway whose side-posts still
remain.

In South-East Spain the brothers Siret have found corridor-tombs in
which the chamber is cut in the rock surface and roofed with slabs; the
entrance passage becomes a slope or a staircase. Here we have a parallel
to the Giants' Graves of Sardinia, which are built usually of stone
blocks on the surface, but occasionally are cut in the solid rock.
Other tombs in the same district show the common megalithic construction
consisting of a base course of upright slabs surmounted by several
courses of horizontal masonry (Fig. 14). The chamber is usually round,
and may have two or more niches in its circumference. It is roofed by
the successive overlapping or corbelling of the upper courses. The vault
thus formed is further supported by a pillar of wood or stone set in
the centre of the chamber. On the walls of some of the chambers there
are traces of rough painting in red. The whole tomb is covered with a
circular mound. In the best known example at Los Millares there are
remains of a semicircular façade in front of the entrance, as in many
other megalithic monuments.

[Illustration: FIG. 14. Corridor-tomb at Los Millares, Spain.
(After Siret.)]