  Two-dimensional second-order topological superconductors host
zero-dimensional Majorana bound states at their boundaries. In this work,
focusing on rotation-invariant crystalline topological superconductors, we
establish a bulk-boundary correspondence linking the presence of such Majorana
bound states to bulk topological invariants introduced by Benalcazar et al. We
thus establish when a topological crystalline superconductor protected by
rotational symmetry displays second-order topological superconductivity. Our
approach is based on stacked Dirac Hamiltonians, using which we relate
transitions between topological phases to the transformation properties between
adjacent gapped boundaries. We find that in addition to the bulk rotational
invariants, the presence of Majorana boundary bound states in a given geometry
depends on the interplay between weak topological invariants and the location
of the rotation center relative to the lattice. We provide numerical examples
for our predictions and discuss possible extensions of our approach.
