Galería is just one of the archeological sites in the Sierra de Atapuerca complex in Spain. This site was excavated between 1975 and 1995.It is a large cave with a vertical shaft near the mouth of the cavern (the vertical shaft made it all the way up to the top of the ridge that the cave was located on, acting as a natural animal pit).
The cave of Galería was not occupied in as intense a manner as some of the other Sierra de Atapuerca
sites, but it has still yielded a weath of artifacts (1400 stone implements, 6150 bone remains of large mammals, abundant microvertebrae remains and two human remains were found).
The Galería site dates to the Middle Pleistocene era (as far back as 450,000 years ago). The cave appears to have been most heavily occupied at the oldest ages, with a continual decrease in activity over the years. The most recent activity (chronologically), were merely scavenger activity. But the older levels show a wider range of activity (a lot more hunting mainly). The predominant choice for these early hunters was the local horses.
The Galería was very poorly lit (it really only had light near the entrance, some which came from the vertical shaft). So all evidence of tool production was concentrated near the mouth of the cave (with no prodocution at all newer than about 250,000 years ago). Perhaps one of the reasons that the cave was so lightly occupied was the natural animal trap (that was directly over the only lit area). Horses and other animals would fall through the hole on a regular basis (which was a great source of food, but lets face it, falling horses are dangerous). There was one period of definate fulltime occupation (as marked by herbivore fossils with cut marks, but no tooth marks). Later time periods showed a much lesser degree of human activity, along with a marked rise in carnivores using the cave for hunting.
By 120,000 years ago the cave was almost completely filled in by sediments. This is the point that the fossil record ceases to produce any newer remains.