The process sedimentology of tills is crucial to the understanding of the glacier ice-bed interface as a complex depositional, erosional and shear boundary layer. Consequently, it also plays a central role in deciphering the genesis of enigmatic subglacial bedforms such as drumlins, flutings and ribbed terrain. Yet, unlike the study of other boundary layers such as those that operate at the bed of fluvial, aeolian and deep water systems, our knowledge of subglacial process-form relationships is relatively impoverished, largely due to the inaccessibility of glacier and ice sheet beds....