Material is transported by the sea in four different ways. This is usually how material is moved and later dropped (deposited) to form features such as beaches and spits.
This is when rocks and heavy boulders are dragged along the sea bed.
This would usually occur when the waves do not have enough energy to carry the material in the water.
This is when smaller boulders are bounced along the sea bed.
Material such as sand grains, are light enough to be carried along in the water in suspension.
Lime from chalk and limestone rocks dissolves and is carried in solution - invisible to the naked eye but can be seen by the milky appearance of the sea. (Remember the picture of the Sussex Coast?)