More specifically, it would be a clastic sedimentary rock, which is formed from fragments of other rocks. The specific type of clastic sedimentary rock depends on the size of the particles:
* Conglomerate: If the pebbles are large and rounded.
* Breccia: If the pebbles are angular and large.
* Sandstone: If the particles are sand-sized.
Let me know if you'd like more information about any of these rock types!
