The sandstone at the base of Maudes Crack has veins of conglomerate rock mixed in with the sandstone. These little round quartz pebbles were once tumbled along a river bottom. The quartz came from the distant Appalachian mountains. This type of sedimentary rock is called terrigenous, meaning it was formed from the weathering of prexisting rocks (white quartz, in this case) and transported to another area. Conglomerate rocks contain three "ingredients":
1. Clasts - these are the larger, easily visible pieces, such as the larger grains of sand and the pebbles
2. Matrix - this is the smaller sediment around the pebbles
3. Cement - this is the substance that holds the matrix and clasts together, a type of mineral "glue", it can be silica, iron oxide, or calcite.
Conglomerate rocks has clasts of rounded pebbles, breccia has clasts of broken, angular rocks.