The R-matrix theory of nuclear reactions is discussed for the situation where distant levels must be included and is successfully applied to the elastic scattering of protons by l2C in the energy range ELAB = 10-11� 5 MeV, where the resonance levels are overlapping. Definite spin and parity assignments are made for three levels in this region by comparing the predicted excitation functions at several angles of scattering with experiment. Previously unexplained polarization data are explained by this analysis. The optical.model potential is found to be parity dependent for ELAB=8.5 MeV and yields a close fit to the available data at ELAB = 8�5 MeV.