Sea balls are tightly packed balls of fibrous marine material, recorded from the seashore. They vary in size but are generally up to 7 centimetres (2.8 in) in size. In Edgartown, Massachusetts a longish sea ball around 45 centimetres (18 in) in diameter has been found. Others have been reported at Dingle Bay in Ireland. They may occur in hundreds and are composed of plant material, in majority seagrass rhizome netting torn out by water movement.