3.3 Bird's eye views of our excavations

Bird's eye views of our excavations will be offered but for more details, see Walker and Gibert in press. At Cueva Negra 4 sedimentary units are recognizable (Figure 4). Unit 1 comprised rubble in powdery, dark-grey soil. Some lay in deep hideaway and storage pits which, following the Civil War, were dug into consolidated Pleistocene yellow-orange sediment (Figure 3, Figure 4; Plate 18), and a low dry-stone revetment (an iron clasp-knife lay in it) under the front of two huge superimposed fallen boulders (protecting the highest part of unit 2 in their pediment: Plate 19) all of which formed the rear wall of a vanished flimsy lean-to.

Plate 18: Cueva Negra: Excavation in progress of units 2 and 3; at left part of a modern storage pit is seen; a fallen boulder is seen in the section. (Photo M. J. Walker)
Plate 19: Cueva Negra: After removal of a large boulder in the entrance, a modern drystone revetment was identified and excavated. (Photo M. J. Walker)

Excavation began behind these boulders, and their destruction has afforded a continuous area (25m² under excavation) from inside the cave out to the terrace. Only a few 1m deep storage-pits interrupt it. Unit 2 contains only middle palaeolithic artifacts (in unit 1 modern objects and a few Roman and late prehistoric artifacts occur). Its weathered surface and upper part were hardened by calcium carbonate precipitated from dripping water. Unit 2 consists of sand and bioclastic fragments eroded from the cave roof and 15% of loess-size soil particles. It is fractured by vertical retraction fissures. Loess and retraction fissures characterize arid pleniglacial soils. Unit 2 is yellowish apart from ephemeral diffuse patches of reddish-brown hue (lateritic lenses?).

Like unit 2, unit 3 was deposited horizontally. We have excavated over 6m². It begins with a weathered surface that is sometimes a very thin calcrete breccia of small gravel. Loess-size particles form under 10% of its uppermost compact yellowish soil. It is interrupted by three discontinuous erosion surfaces and by buried, sloping, frost-shattered scree in the western part of the rock-shelter. This scree represents an ancient roof fall that underwent partial dissolution by water dripping down from solution holes in the roof; therefore sediment never filled the cave up to the roof. Perhaps discontinuous erosion surfaces were formed by water pouring down through retraction fissures (as it still does during heavy rain). Lower down, silt-size grains once more represent 15% of particles. Excavation of unit 4, 2.5m down, is underway in only 1m² (Plate 20) where it begins with small broken slabs of calcrete 50-100mm thick; artifacts seem plentiful in it.

Plate 20: Cueva Negra: Deepest area under excavation at present. (Photo M. J. Walker)

Destruction of a fallen boulder blocking the western half of the cave mouth revealed a bovid horn on the surface of unit 2 (in shape and size strikingly similar to horns of small adult American bisons, though very likely it belonged to a young aurochs). In the eastern half, two superimposed fallen boulders protected a pediment of unit 2 soil in which another shattered boulder was embedded lying over both an elephantid mandibular ascending ramus (Plate 21) covering a tortoise shell, and a small Rhinoceros skull and mandible (Plate 22). Without elephantid teeth, we cannot say if it was mammoth or elephant (mammoth occurred at Carihuela Cave in nearby Granada). The rhino may well be a young Dicerorhinus hemitoechus, though its badly damaged teeth preclude specific identification. Associated with it were three chipped stone pieces and a Neanderthal canine tooth (CN-2), whilst close by there lay a Neanderthal ulnar shaft (CN-3) (Plate 4). Deeper in unit 2 and further back a much larger adult rhinocerotid hemimandible was found, close to the top of another huge fallen boulder covered by unit 2 sediment but lying on the surface of unit 3.

Plate 21: Elphantid mandible. Scale in cm (Photo M. J. Walker)
Plate 22: Rhinocerotid skull, vertebra and mandible, with stone flakes touching it. CN-2 was found among vault fragments of the skull which is undergoing restoration. Scale in foreground in 10 cm divisions. (Photo M. J. Walker)

On the other side of this, a frontal fragment of Giant Deer (Megaceros) sprouting massive antler crown-beams was excavated in an upper zone of unit 3. Excellent preservation of abundant minute skeletal components of birds and very small mammals hints that large mammals were selectively dismembered elsewhere, otherwise more of their postcranial bones should have survived in the sediments. Did scavenging humans preferentially retrieve head-parts of beasts already partly devoured by hyaenas or other carnivores? Our north-facing rock-shelter perhaps made a good look-out for scrutinizing herbivore or carnivore (including vulture) activity in water-meadows and swamps of the former flood-plain in a gorge shallower than today, and thence southwards over flattish uplands behind it, or northwards down the Quípar valley.

There may be spatiotemporal groupings of stone artifacts: seven occurred in C2g(3p) (metre square C2g, unit 3, spit p) 1m below the large rhinocerotid hemimandible, whilst 1.1m further down, nine occurred in C2a(4g) - the deepest part yet reached. Similar 50mm spits in other metre squares have few or no struck flakes or retouched pieces. Frangibility of local chert nodules means knapping spalls and chips abound, some even showing use-wear. Such "wasters" cannot be overlooked in eventual statistical analyses of spatio-stratigraphical distributions, though space precludes giving details here. Planned lithic-refitting may throw light on spatiotemporal aspects. Because only unit 2 has been excavated to any great extent, prudence counsels against over-interpreting spatial comparisons/contrasts.

Excavation began atop the Sima de las Palomas breccia column after building a scaffolding tower in 1994 (Figure 5, Figure 6; Plate 13) and by 1995 we had excavated nearly 1m² of our upper cutting to a depth of 1.5m. We chose a place where the continuous 18m breccia column drops almost vertically away, but where previous erosion let us quickly clean and inspect three right-angled sections in the top of the exposed breccia face. This lessened risks of mistaking finds from one unit with those from another, were the stratigraphy to be as strongly inclined as is common in shafts: surprisingly, all sections showed horizontal stratigraphy. Cemented bone breccia and scree touching the overhanging rock roof were removed in horizontal stages designated as spits Ia and Ib of an arbitrary "unit I". By contrast, lithostratigraphical unit 1 is a tiny lens of breccia adhering to the overhang; either it is atavistic and preceded Ia or else an infilling after its incomplete erosion. Ib incorporates the edge of an ancient rock-fall down the shaft. Unit 2 is characterized by horizontal accumulation of angular scree. I, 1, and 2 are of yellowish-brown soil (Plate 13). I and 2 have many bones, including human ones, and middle palaeolithic artifacts. A northern upper cutting extension, begun in 1995, is now almost at the same depth the original cutting.

Our lower cutting, initially 2x1m, was opened in 1995 in the floor of a "niche" of the main chamber (Figure 5, Figure 6). It is now 2.2m deep and extends another 2m under a rock overhang. Below 1.5m of disturbed soil and rubble, perhaps deposited in two stages during mining operations - the lower one has black burnt lenses - we find compact dark soil containing few finds, burnt lenses, retraction fissures, diffuse reddish zones (due to gamma-hydrous iron oxide?), and corroded calcrete slabs lying underneath them - perhaps representing broken pieces of calcrete still adhering to overhanging rock. Expansion and deepening of the lower cutting may throw light on ancient Pleistocene sediments and/or possible karstic drainage tubes giving access from the hillside.

Largely unexplored traces of burnt soil containing burnt bone cling to the rear wall of the "niche", above the main chamber floor-level and over our lower cutting, hinting at similarity to grey lenses of burnt soil some 2m above the main chamber floor-level in the breccia column.

Those in the breccia column underwent burning: gas chromatography implies organic matter was burnt out, and X-ray diffraction highlights a preponderance of sand that implies thermal effects, given the presence of carbonates, phosphates, as well as sand, in over- and underlying sediments. Although excavation cannot reach the lenses for several years, conceivably they contain fossils - perhaps four very archaic, burnt, hominid bones found while clearing rubble beside the foot of the breccia column: a low, robust mandibular body (like some from Atapuerca Sima de los Huesos, "Bone hole"), an archaic, robust temporal squame, a frontal fragment with the lateral part of a right supraorbital torus and frontal trigone (recalling Steinheim's), and a central part of a left supraorbital torus (Plate 23, Plate 24). Aragonite crystals in nearby breccia offer uranium-thorium estimates of last interglacial age, and a late Middle Pleistocene Panthera pardus cf. lunellensis skull was plucked by spelaeologists out of low breccia.

Plate 23: Sima de las Palomas: robust burnt temporal fragment CG-12. Scale in 1cm divisions. (Photo M. J. Walker)
Plate 24: Sima de las Palomas: medial fragment of left frontal and supraorbital torus CG-15. Scale in 1cm divisions. (Photo M. J. Walker)

If low breccia here contained hominids, were their bones dropped by panthers and did sporadical lightning strikes spark fires of brushwood that had fallen down the shaft? Or did hominids climb down a dangerous deep shaft and light fires at the bottom? Or did they enjoy an easy way in, maybe a karstic tube now blocked up - even, perhaps, one of which all traces were dynamited to smithereens in driving a horizontal mine level along its course?


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Last updated: Wed Dec 23 1998