The limestone cliffs evident on the eastern face of the Grand Veymont are composed of Glandasse or Urgonian limestone of Lower Barremian age, laid down between 125 and 130 million years ago. The bedding planes dip at roughly 30°, the angle of the western slopes. Its geology is similar to that of the haut plateaux of the Vercors Massif to the west, but differs from that of the valley to the east, which is monoclinal in structure, although still of Lower Cretaceous age. In the last ice age, a glacial tongue descended from the north-eastern slopes into the valley of Gresse-en-Vercors, depositing a glacial moraine which is visible today to the west of the village. However, there is no longer any permanent ice or snow on le Grand Veymont.