could not have produced the sorting of the different parts of the skeletons of the animals whose remains were found in the lower deposit. Other possible agents of accumulation, such as carnivores, could not account for the presence of charcoal and flaked flint in the deposit.

Given these factors, Delgado concluded that there was no known natural cause that could account for the mixed accumulation inside the cave of sands, éboulis, bones, and artifacts. He therefore developed his own alternative explanation. He viewed the formation of the deposit as a gradual and slow process, not as the result of one or several catastrophic flooding events. Otherwise, he thought, it would be impossible to explain either the presence of bone at all depths or the vertical and horizontal discontinuities in the concretion of the sands at all levels. He therefore thought that the remains of human dwellings suggested by the association of the animal bones, charcoal, and artifacts had gradually been incorporated into the deposit as it built up. The provenience of the sandy matrix was thought to be the diluvial deposits outside the cave. Since no natural process was identified by geological authorities at the time as a possible cause for such a gradual filling of a cave by external sediments, Delgado attributed this process to human action: the sands were thrown in to elevate the floor of the cave and thus facilitate human access through its vertical entrance. Although this explanation is certainly wrong in terms of the specific agency invoked, it is certainly much closer to modern ideas regarding the nature of the process described than the theories current in his time.

Another remarkable feature of Delgado’s monograph is the attention given to the discussion of taphonomic (site formation) issues. Taphonomic observations were instrumental in rejecting the action of flooding waters as an explanation for the origin of the lower deposit, and they also played an important role in sustaining Delgado’s evaluation of its faunal content. For instance, rabbits and birds were represented mainly by mandibles (jawbones) and broken long bones. There were far fewer vertebrae and pelvises than could be expected given the number of individuals represented by the mandibles, and ribs were almost completely absent. The minimum number of rabbits, based on the counting of mandibles, was over 1,000. As for the larger mammals, Delgado observed that spongy bones were generally lacking and that the bones richest in marrow were the most fractured. But unlike the herbivore bones, the carnivore bones were generally intact and did not show any signs of having been transported by water, which was another argument against the flooding hypothesis as an explanation for the deposit’s origin. Carnivores were also mostly represented by mandibles, and the majority of the animals found were young individuals. Delgado interpreted these observations as confirming his conclusion that humans were the agents responsible for the bone accumulation. At that time there was no known natural cause that could account for the apparent sorting of the different skeletal parts and the differential preservation of herbivore and carnivore bones.

With the benefit of hindsight, we now known that Delgado’s conclusions are not completely correct. The variety of large, medium, and small carnivores (especially wolves) identified from the deposits suggests that the cave was also a carnivore lair. The important point here, however, is that in order to substantiate his behavioral interpretation, Delgado took what would now be considered the correct scientific approach. He tried to derive from the characteristics of the bone assemblage itself objective criteria that might lead to the identification of the agent or agents responsible for its deposition and modification. What was lacking at the time was a set of actualistic reference studies that might provide the patterns against which it would be possible to validate such identifications. This and Delgado’s predisposition to favor human action as the explanation for the site’s characteristics (an understandable inclination, given the research design that drove him) probably biased his diagnosis.

Delgado reported on the Neolithic human bone remains from the cave’s upper deposit with a similar taphonomic approach. Their great fragmentation, the sorting of the different parts of the skeleton, and the fact that some bore what he thought to be marks of cutting by tools led