During the Early Pleistocene, the climate at Atapuerca was dry and cold. A large ice cap lay over the Pyrenees mountain range to the north of Atapuerca. Runoff from the glaciers created numerous streams in the Atapuerca region. Throughout the Pleistocene, the Iberian Peninsula (modern Spain and Portugal) was a refuge in southern Europe, providing a more temperate habitat even as glaciers covered northern Europe.

TD 4 Illustration by Mauricio Antón

Layer 4 (TD 4)
The sediments in Layer 4 (also known as TD4) are approximately one million years old and contain the oldest animal remains found at Gran Dolina. Researchers have discovered the fossilized remains of rhinoceros, deer and jaguars from this period, as well as some stone tools. The layers below this level have not yet been examined at Gran Dolina because so far they have not yielded material of interest. The sediments in Layer 4 consist primarily of yellow and brown sands containing nodules of limestone.

Are there other archaeological sites along the railway trench?
Yes. Other sites are located along the railway trench near Gran Dolina. At the sites known as Galeria and Elefante, for example, researchers have found stone tools and a variety of animal remains.