The detrital sedimentary rock made up of clay-sized particles that require no cementation to hold together is called claystone.

Here's why:

* Detrital: This means the rock is made up of fragments of other rocks and minerals.

* Clay-sized particles: These are the smallest particles, less than 0.0039 inches in diameter.

* No cementation: The clay particles are so fine and tightly packed together that they naturally stick together without needing additional minerals to bind them.

Claystone is a common sedimentary rock that is often found in layers. It is typically very fine-grained and feels smooth to the touch.