Archeological research in areas that surround the Trabancos River, between the villages of Castrejón and Pollos (Valladolid province) have been compared with the specialized bibliography and the published geological charts ("infra"). This produced identified a sequence of river terraces as follows, on the left hand margin of the chart: TT-1 platform (the most ancient, at +35/40 meters over the flood plain); the TT-2 platform (the second one at +25/30 meters); the TT-3 platform (at +15 meters over the floodplain); and the TT-4 platform (at +10 meters, the last and most recent).