Pech II was discovered by Bordes in 1948, due in part to the fact that some of the talus of this locale had been cut away in the construction of a rail line that runs parallel to the cliff at this point. He excavated there from 1949 to 1951 and then again from 1967-1969. Both outside the mouth of the cave and within the cave itself was an occupational sequence which began with the so-called Meridional Acheulian (now considered by many to be an early Mousterian) followed by a variety of mostly Typical Mousterian industries. Schwartz and Blackwell published two U-series dates from Pech II and two from Pech I, and Grün et al. published a series of ESR dates based on 29 teeth from Pech II. Both sets of dates give a consistent picture, though the ESR dates provide more detail. They indicate that Pech II was occupied between oxygen-isotope stages 6 and 3, with a break in the sequence between the lower layers 5-9 (stage 6) and the upper layers, 2-4, which seem to span from middle stage 5 until stage 3.