Notas sobre cuevas en arcilla en el barranco del Abejar (Bardena Negra).

New cavities in clay found in the North Abejar Canyon and in the South flank of the Snake Plain are described (Black Falls, Black Bardena). The cavities are developed in a unit of ochre and gray clays belonging to the Tudela Formation (of Miocene age, Tertiary). The ravines have on its walls small cavities and pipes generated by piping. The larger cavity found is a cave that connects with a chasm higher, and continues forming a gully on the flank. Said cavity reaches 72 m of development and illustrates very well the general mechanism of genesis of cavities in clay. The note discusses the traits and processes observed.