  Graphene layers are known to stack in two stable configurations, namely ABA
or ABC stacking, with drastically distinct electronic properties. Unlike the
ABA stacking, little has been done to experimentally investigate the electronic
properties of ABC graphene multilayers. Here, we report the first magneto
optical study of a large ABC domain in a graphene multilayers flake, with ABC
sequences exceeding 17 graphene sheets. The ABC-stacked multilayers can be
fingerprinted with a characteristic electronic Raman scattering response, which
persists even at room temperatures. Tracing the magnetic field evolution of the
inter Landau level excitations from this domain gives strong evidence to the
existence of a dispersionless electronic band near the Fermi level,
characteristic of such stacking. Our findings present a simple yet powerful
approach to probe ABC stacking in graphene multilayer flakes, where this highly
degenerated band appears as an appealing candidate to host strongly correlated
states.
