Here's why:
* Sedimentary rocks are formed from the accumulation and cementation of sediments. These sediments can range in size from microscopic clay particles to large boulders.
* Coarse-grained sedimentary rocks are defined by their large grain sizes. Pebbles and boulders fall into this category.
* Examples of coarse-grained sedimentary rocks include:
* Conglomerate: Made up of rounded pebbles and cobbles cemented together.
* Breccia: Similar to conglomerate but contains angular fragments.
So, to answer your question directly, coarse sedimentary rocks can absolutely be composed of pebbles or boulders.
