DINOSAUR TRACKS AT THE LEVEL OF THE LOWER CRETACEOUS IN MUONG-PHALANE, SAVANNAKHET PROVINCE (LAOS)

In 1993, a Franco-Lao field-work team found three levels with dinosaur footprints in Muong Phalane, Savannakbet Province(Laos). The footprin ts are visible on the bank of the Sang Soy River on a tabular bedded s andstone belonging to the ''Gres superieurs'' Formation, dated by the occurrence of fresh water pelecypods (Trigonioidacea) from the end of the Lower Cretaceous. we have registered 13 theropod footprints on the lower slab, 8 footprints of an ornithopod and 38 of sauropods on the medium one, and on the upper one, 2 theropod footprints similar to tho se of the lower slab. The different trackways allowed us to estimate t he speed of the theropod at 5 km/h with a hip-height of 170 cm, and th e speed of the ornithopod at 6 km/h with a hip-height of 210 cm. The f acies of the sediment collected in Muong Phalane and the occurrence of ripple-marks on the slabs seem to be related to a flood pain.