Wikimedi'Òc

McDonald Creek (Red Rock Point, Going to the Sun Highway, Glacier National Park, Montana, USA) 2 (19856616169).jpg - Ser Amantio di Nicolao

Mudcracks in argillite (Grinnell Formation, Mesoproterozoic, ~1.45 Ga; Glacier National Park, Montana, USA) 2.jpg - Ser Amantio di Nicolao

Mudcracks in argillite (Grinnell Formation, Mesoproterozoic, ~1.45 Ga; Glacier National Park, Montana, USA) 3.jpg - Ser Amantio di Nicolao

Mudcracks in argillite (Grinnell Formation, Mesoproterozoic, ~1.45 Ga; Glacier National Park, Montana, USA) 4.jpg - Ser Amantio di Nicolao

Mudcracks in argillite (Grinnell Formation, Mesoproterozoic, ~1.45 Ga; Glacier National Park, Montana, USA) 5.jpg - Ser Amantio di Nicolao

Argillite, Glacier National Park.jpg - DaveGinOly