They are sedimentary rock. Four examples being chalk, sandstone, limestone and slate.
Layers of sediment are pressed under the earth for thousands and millions of years, and solidify into rock.
The stage of sedimentary rock formation where sediment is pressed together to form layers is called compaction. During this process, the weight of overlying sediments compresses the deeper sediments, reducing their volume and expelling water. This leads to the formation of distinct layers or strata in the rock. Compaction is a crucial step in the lithification process, which ultimately transforms loose sediment into solid rock.
rock.
Shale is made from layers of mud and clay pressed together. :)
Pieces of sediment that have been pressed and cemented together form sedimentary rock. This process occurs over thousands of years as layers of sediment accumulate and are compacted under pressure, eventually forming solid rock. Sedimentary rocks can include sandstone, limestone, and shale.
Trilobites are ancient fossils commonly found in dome-shaped rocks composed of thin layers of sediment. These creatures have a hard exoskeleton that can be well-preserved in sedimentary rocks.
Resin pressed in sediment becomes amber after undergoing a process of fossilization. Amber is a hardened tree resin that can trap and preserve organisms and plant material, providing a window into Earth's ancient ecosystems.
Gravity causes layers of sediment to be horizontal because as sediment deposits, it settles evenly due to gravity pulling the particles downwards. Over time, as more sediment accumulates, the weight of the new layers causes the underlying layers to compact and settle into a horizontal orientation.
They get grounded into sediment and then get pressed together.
Cementation
compaction
Compaction.