Kälin Daniel, Kempf Oliver (2009) :
High-resolution stratigraphy from the continental record of the Middle Miocene Northern Alpine Foreland Basin of Switzerland. N. Jb. Geol. Paläont. Abh. 254/1-2, 177-235
On the eastern side of the Napf alluvial fan, near Wolhusen, a bentonite horizon has been described by PAVONI & SCHINDLER (1981). A correlation to the bentonite levels of the Zürich region is not yet established, however, given its lithostratigraphic
position the Wolhusen bentonite is most probably equivalent to the Urdorf bentonite.
