The Soja Nappe is a small tectonic unit of the Eastern Lepontic (Ticino Culmination) located between the overlying frontal part of Adula Nappe and the underlying Simano Nappe. To the north, it extends into the Garzott Slices located in the core of the Lunschania Antiform and surrounded by the Piz Terri-Lunschania Nappe. It includes a polycyclic crystalline basement covered by Permian to Jurassic sediments.

Dolomitische Abfolge, mit wenigen geringmächtigen Kalklagen, im Dach der Soja-Decke.

Gneiss phengitique résultant du métamorphisme d'un grès arkosique avec quelques intercalations conglomératiques.

Antico gneiss policiclico nel nucleo della falda della Val Soja: gneiss chiaro a due miche, a grana minuta fino a media, fortemente scistosa.