The diagrams illustrate the process of forming sedimentary rock in coastal areas.
The first two diagrams depict how the boulders, formed as a result of mountain cracking, slide down into the river water. Afterwards, these stones move downstream until they reach the lowest water level.
The last two diagrams show the process of forming the sedimentary rock. As a consequence of erosion, huge stones become much smaller and transform into pebbles. Initially, these pebbles settle evenly under the water level, where they mix with other materials like sand and cement. Due to high and low tides, in time this sediment accumulates closer to the mountain base – the lowest part of the mountain – and creates the coasts. Additionally, the coast comprises a plethora of sediment levels: from big rocks to tiny pebbles.
Overall, the process of forming sedimentary rock consists of two stages. Firstly, boulders are formed as a result of fissures. Then they move to the base of the mountain. Secondly, these stones transform and mix with other materials.
