Boulders
Boulder
Natural rock fragment larger than 10 inches
In geology, a boulder (or rarely bowlder)[1] is a rock fragment with size greater than 25.6 cm (10.1 in) in diameter.[2] Smaller pieces are called cobbles and pebbles. While a boulder may be small enough to move or roll manually, others are extremely massive.[3] In common usage, a boulder is too large for a person to move. Smaller boulders are usually just called rocks or stones.