The mountains of Sawtooth National Forest have a varied geological history. The northern Sawtooth Mountains formed from the Eocene Sawtooth batholith, while south of Alturas Lake the Sawtooth, Smoky, and Soldier mountains formed from the Cretaceous granodiorite of the Idaho Batholith. Foothills of the Smoky Mountains are from the Pennsylvanian and Permian Dollarhide formations. The White Cloud Mountains are underlain by the gray granodiorite of the Idaho batholith, while some of the exposed rock is baked impure limestone from the Permian Grand Prize Formation.