Paleozoic conglomerates tend to display evidence of metamorphic pressures. Look closely, however, what looks like conglomerate can be concrete. Concretion derived from Quaternary marine coastal plain sediments. Concretions sometimes are encrusted with coral. Beach rock derived from Quaternary coastal plain sediments.
Beach rock is the host material of most beach fossils.
The matrix consists of fine to coarse sand, even conglomerate. Sand is cemented with calcite or limonite. This cobble of well cemented beach rock contains jingle shells, oysters, gastropods, shark vertebrae, and spruce pine cones. Coal occurs naturally in abundance in pre-anthropogenic sediments.