Bowlder
Bowlder ({not transcribed}) , noun
[Compare Swedish bullra to roar, rattle, Danish buldre, dial. Swedish bullersteen larger kind of pebbles; perh. akin to English bellow.]
1.
A large stone, worn smooth or rounded by the action of water; a large pebble.
2.
(Geology) A mass of any rock, whether rounded or not, that has been transported by natural agencies from its native bed. See Drift.
Collocations (2)
Bowlder clay , the unstratified clay deposit of the Glacial or Drift epoch, often containing large numbers of bowlders.
Bowlder wall , a wall constructed of large stones or bowlders.
Also: Boulder