from The Century Dictionary.
- Filled with drift: the condition of preglacial depressions, which were crossed by the great ice-sheet and filled with its morainal deposits.
Sorry, no etymologies found.
A section of the valley may have been blockaded with morainic waste, and the lake formed behind the barrier may have found outlet over the country to one side of the ancient drift-filled valley.
He realized with a quiver of dismay that he had mistaken a huge drift-filled fissure, between a jutting crag and the wall of the ridge, for the solid, snow-covered ground.
Several ancient drift-filled channels on Thibert Creek, blue at bed rock, were exposed and had been worked.