from the GNU version of the Collaborative International Dictionary of English
- adj. masses of stone which have been transported from their original resting places by the agency of water, ice, or other causes.
Sorry, no etymologies found.
You will, I am sure, rejoice with me at the adhesion of C. Darwin to the doctrine of ancient glaciers in North Wales, of which I send you a copy, and which was communicated to me by Dr. Tritten, during the late meeting at Manchester, in time to be quoted by me versus Murchison, when he was proclaiming the exclusive agency of floating icebergs in drifting erratic blocks and making scratched and polished surfaces.