Dissolved minerals in the water are gradually precipitated, filling in the spaces between the rock fragments. The layers of sediment turn into rock strata. Sedimentary materials are are also deposited by wind or glaciers. The strata of sedimentary rocks are often colored by minerals. A reddish color, as in the picture above, is caused by iron oxide, also called rust.
Igneous rocks begin with molten material.
Sometimes sedimentary rocks are heated up when they are deep in the earth, and this can help to fuse the particles of sediment together. Such rocks retain their layered structure. Millions of years have gone by and there are many layers of deposited sediment now. This part of the earth has been sinking, and the sea is much larger now. More sediment has been deposited.