C or R horizon?

We saw a Pedon in flooded soil in footslope in calcareous shale parent material in Udic soil moisture
there are lithogenic discontinuous in soil pedons

A 0-12
C 12-29
--- ?? 29-41 (a layer with gravel, pebble and cobble of shales without soils)
3C 41-53
--- ?? 53-60 (a layer with gravel, pebble and cobble of shales without soils)
5C1 60-71
5C2 71-150

whats ?? C or R horizon?