Conglomerate (geology)

a rock that is composed of smaller rounded rocks cemented together

A conglomerate is a rock consisting of individual clasts within a finer-grained matrix that have become cemented together.

Carmelo Formation (Conglomerate) at Point Lobos, California
Puddingstone outcrop

Conglomerates are sedimentary rocks consisting of rounded fragments and are thus differentiated from breccias, which consist of angular clasts.[1] Both conglomerates and breccias have clasts larger than sand (>2 mm).


  1. "Conglomerate Rocks." Conglomerate Rocks on Rock Hound. Archived 2010-07-26 at the Wayback Machine Rock Hounds. Retrieved on July 29, 2007.
A puddingstone: pebbles from a former beach cemented by silica
A polished puddingstone snuff bottle