The northeastern part, known as Plateau des Lacs, is dotted with mountain lakes such as Veche, Agneau, Noir, Culasson, and Fourchu.

The northeastern fringe, encompassing the Lignarre and Romanche watersheds, belongs to the Oisans region.

[2] The massif consists of three parallel chains oriented north-south and arranged from east to west.

[3] In contrast, the western chain of Sénépy and the Conest mountain consists of slightly clayey limestones from the Lower Lias period.

Additionally, the western flank features outcrops of calcschists from the Upper Lias period.