  In the presence of external magnetic field the Fermi-liquid state supports
oscillatory spin modes known as Silin modes. We predict the existence of the
generalized Silin modes in a multivalley system, monolayer graphene. A gauge-
and Berry-gauge- invariant kinetic equation for a multivalley Fermi liquid is
developed and applied to the case of graphene with extrinsic spin-orbit
coupling (SOC). The interplay of SOC and Berry curvature allows for the
excitation of generalized Silin modes in the spin and valley-staggered-spin
channels via an AC electric field. The resonant contributions from these modes
to the optical conductivity are calculated.
