Dolmen de Cubillejo de Lara

The dolmen stands on a small spur formed by the confluence of two streams, in a valley dominated to the north by Peñalara and to the south by the sierra de las Mamblas. The landscape lies in the transition zone between the Tertiary Basin of the Northern Submeseta and the western flank of the Iberian Cordillera, the sierra de la Demanda. The geology is varied: limestones, conglomerates, clays and alluvial deposits.

The monument can be reached by taking, from the N-234 Burgos-Sagunto road, the track that leaves the road in the direction opposite to the abandoned village of Mazariegos; it lies 1600 m along this track, just before a bridge. A better track also leads to it from the village of Cubillejo de Lara. Its position beside a junction of streams, a track and a drove road (the Cañada Real de las Merinas) made the place a notable landmark.

The structure is a passage grave: a burial chamber and an access passage buried in a mound of earth and stones. The mound is the worst-preserved part of the monument. It is only slightly defined and of modest size, its shape governed by the edges and slopes of the streams that bound and erode it, and by the trenches and clearance made during the investigation. An oval plan is surmised, with its long axis along the passage, and its height is not great, although some orthostats of the chamber approach 2 m.

The chamber is circular, between 4.5 and 6 m in diameter, and was originally formed of eleven orthostats of limestone and conglomerate, of which ten survive. Most are unworked natural blocks from a small nearby quarry, set upright and inclined inwards to ease roofing. Unusually, the blocks are not of uniform height; the tallest reaches 2.25 m in height and 0.40 m in thickness, which would explain rectangular and semicircular recesses for the roof seen in the upper part of the lower blocks.

A peristalithic ring of fourteen blocks, as large as those of the chamber, encircles the chamber on the outside, with a deliberate infill of small stones between the two. In most dolmens such a ring served to contain the earth of the mound, like a buttress. Its presence links the dolmen of Cubillejo with the megalithism of the west of the Peninsula, the monuments of the Beira (Portugal) and those of Extremadura and Salamanca.

The passage, oriented to the south-east, is formed by two parallel walls of six slabs each, set lengthwise, with some external reinforcement. It is 10.5 m long and 1.5 m wide, and its height decreases from 1.5 m at the entrance to the chamber to 0.75 m at the opposite end. The roofing is the least known part. In the chamber floor a hole was observed that probably held a central post or pillar, and two other circular hollows were seen inside the passage. The passage was probably covered with lintels like the one placed at the entrance to the chamber, which had fallen into the passage before the work of 1970. The floors of chamber and passage are unpaved and consist of compact clay.