Pebble

This type of beach has armoring characteristics with respect to wave erosion, as well as ecological niches that provide habitat for animals and plants.

Pebbles left above the high water mark may have growths of organisms such as lichen on them, signifying the lack of contact with seawater.

[citation needed] Here, they entered lakes and ponds, and form in rivers, travelling into estuaries where the smoothing continues in the sea.

[2] Beach pebbles form gradually over time as the ocean water washes over loose rock particles.

The colors range from translucent white to black, and include shades of yellow, brown, red and green.

Some of the more plentiful pebble beaches are along the coast of the Pacific Ocean, beginning in Canada and extending down to the tip of South America in Argentina.

On Mars, slabs of pebbly conglomerate rock have been found and have been interpreted by scientists as having formed in an ancient streambed.