Two adjacent chambers of the cave of La Chaise, Grotte de Bourgeois-Delaunay (B-D) and Grotte Suard, have been studied. Both were partly filled with detrital sediments containing lower and middle Palaeolithic artifacts and skeletal remains of pre-Neanderthalian hominids. Layers of stalagmitic calcite occur interstratified in the sediments of both chambers. Dates obtained by ²³⁰Th/²³⁴U ratios have provided a time scale for hominid and cultural evolution as represented in this cave. In B-D the lower travertine rests on a breccia containing cranial remains of juvenile Neanderthals. The base of the travertine dates to 151 ± 15 Ky (Ky = 1000 years BP); the top of the travertine yields a date of 112 ± 5 Ky. The travertine contains pollen of an interglacial flora. Overlying detrital sediments 1.2 meters in thickness contain artifacts transitional from Acheulian to Mousterian industries. They are capped by a travertine (Layer 7) whose base is dated at 100 ± 6 Ky, and which is capped by stalagmites ranging in age down to 58 ± 7 Ky. Overlying the travertine is sediment containing first Mousterian, and then Aurignacian artifacts. Near the base of the sediments filling Grotte Suard is a stalagmite layer dated to 249 ± 30 Ky. It contains interglacial pollen and presumably dates to the beginning of the isotope stage 7 interglacial. Neanderthaloid hominid teeth and cranial fragments are found scattered through the overlying sediments, up to a capping stalagmitic layer whose base is dated at 101 ± 7 Ky. The best described hominids from Suard are from a section that was probably overlying the capping stalagmite. The capping stalagmite is temporally correlated with layer 7 of B-D. -- AATA