This group of plutons is reserved for silicic intrusives exposed in the central and northern portion of the Snake Range and Kern Mountains, and also applies to plutons exposed in several ranges in western Utah. Plutons exposed in the Snake Range are primarily light gray, medium to coarse-grained, quartz monzonites but are locally granodioritic in composition, particularly along their intrusive borders (Hose and Blake, 1976). Swarms of garnet-bearing pegmatite dikes are abundant in the Snake Range plutons (Miller and others, 1983). The Kern Mountains pluton is one of the largest intrusive bodies in eastern Nevada, covering nearly 35 square miles, and is mainly composed of granodiorite with minor amounts of quartz monzonite and granite. Like the Snake Range plutons, the Kern Mountains intrusives are penetratively deformed and metamorphosed to varying degrees (Hose and Blake, 1976).

Abundant radiometric dating on the Silver Creek, Osceola, Pole Canyon and Snake Creek plutons give inconsistent results. K-Ar, Rb-Sr and lead-alpha dates on several of these Snake Range plutons give Middle Jurassic ages (about 160 Ma) as well as ages varying from Miocene (17 Ma) to Late Permian (240 Ma) (Lee and others, 1970, 1980; Miller and others, 1983). It is clear that most of the younger ages are the result of thermal resetting related to movement along low-angle normal faults such as the Snake Range decollement (Lee and others, 1970; Hose and Blake, 1976). K-Ar ages are in fact progressively reset from 160 Ma upward in the pluton to 17 or 18 Ma as the detachment fault is approached (Lee and others, 1970). Possible resetting is also indicated in the Kern Mountains pluton where K-Ar and fission track age dates give an Eocene to Oligocene age centering at about 40 +/- 10 Ma, while Rb-Sr ages are Cretaceous at about 72 +/- 7 Ma (Hose and Blake, 1976).

For these reasons it is difficult to call these plutons Mesozoic or Tertiary in a definitive manner, and they are here considered Tertiary-Mesozoic silicic plutonic rocks (Lee, 1980). Although most of the plutons are probably Mesozoic in age and locally reset with Tertiary tectonism, Lee and others (1970) have described and dated plutons such as those near Hendrys Creek that they believe are true Tertiary plutons.