Conglomerate
Carboniferous Conglomerate (Siderite pebbles in matrix, Westphalian 'A'), West Loughton, Lancashire
A fragmental sedimentary, coarse-grained rock, composed of fragments larger than 2mm in diameter cemented in a finer-grained matrix; the consolidated equivalent of gravel. Forms where there is sufficient energy to move large fragments of material. This includes beaches and river systems.