  Low-energy electronic states in monolayer and bilayer graphenes present
chiral charge carriers with unique and unusual properties of interest for
electronic applications. Here, we report the magnetotransport measurements in
the ABC-stacked trilayer graphene as a function of charge carrier density,
magnetic field, and temperature, which show clear evidence of l = 3 chiral
quasiparticles with cubic dispersion, existing in a large, 20x60 sq. microns
device. Shubnikov-deHaas oscillations (SdHO) reveal the Berry's phase 3\pi, and
the marked increase of cyclotron mass near charge neutrality, consistent with
divergent behavior expected for l = 3 quasiparticles. We also observe the
predicted unconventional sequence of quantum Hall effect (QHE) plateaus,
+/-6e^2/h, +/-10e^2/h, ... .
