Answer:
They are clastic sedimentary rocks
Step-by-step explanation:
Sandstones, siltstones and shales are all clastic sedimentary rocks.
Clasitc sedimentary rocks are derived from other rock types.
These rock types typically forms from the suspended and bed load of erosion. The weathering of rocks provides the materials that forms these rock types.
The difference between the three rock types is based on their size. Shales are the finest while sandstones are made up of sandsized particles. Siltstones are in the middle.