The cerebeller surface features folia and sulci.

The outer layer of grey matter is the cortex & is divided into 3 layers

1. Molecular layer: most superficial & composed of neuropils.
2. Piriform layer (Purkinje cells): a single layer of large cell bodies. Their axons project into the white matter, where they synapse with neurons in the cerebellar nuclei. The dendrites project into the molecular layer and make synaptic contacts with granular cell axons.
3. Granular cell layer: situated adjacent to white matter & contains densely packed very small neurons with heterochromatic nuclei.