Final answer:
Shale is the rock made of the smallest sediments, consisting of fine-grained silt and clay particles.
Step-by-step explanation:
The rock made of the smallest sediments is Shale. Shale is a fine-grained sedimentary rock made up of silt- and clay-sized particles. It forms from the compacted and hardened mud and clay found at the bottom of lakes, rivers, and oceans.