  The search for new realization of topologically protected edge states is an
active area of research. We show that a tilt boundary in gated multi-layer
graphene supports topologically protected gapless kink states, associated with
quantum valley Hall insulator (QVH). We investigate such kink states from two
perspectives: the microscopic perspective of a tight-binding model and an
ab-initio calculation on bilayer, and the perspective of symmetry protected
topological (SPT) states for general multi-layer. We show that a AB-BA bilayer
tilt boundary supports gapless kink states that are undeterred by strain
concentrated at the boundary. Further, we establish the kink states as concrete
examples of edge states of {\it time-reversal symmetric} ${\mathbb Z}$-type
SPT, protected by no valley mixing, electron number conservation, and time
reversal $T$ symmetries. This allows us to discuss possible phase transitions
upon symmetry changes from the SPT perspective. Recent experimental
observations of a network of such tilt boundaries suggest that transport
through these novel topological kink states might explain the long standing
puzzle of sub-gap conductance. Further, recent observation of gap closing and
re-opening in gated bi-layer might be the first example of a transition between
two distinct SPT's: QVH and LAF.
