The surface of the cerebellum is extremely strongly folded and provided with very deep furrows. Here one is not talking about whorls (gyri) but about thin leaf-like folds (folia cerebelli). The surface of the cerebellar cortex is approx. 2000 cm2. i.e. comparable to the surface of the large brain.
The bark layer is approx. 1 mm thick and contains 40-50 billion nerve cells, and then mainly in the form of so-called grain cells (very small nerve cells ). The cerebellar cortex thus contains about twice as many nerve cells as the cerebral cortex.
It is now estimated that the cerebellar cortex contains at least 7 (seven!) different types of nerve cells (cerebellar cortex nerve cell types)
The cerebellar cortex is divided into three layers. Ultimately, it lies
the "molecular layer", inside
The "Purkinje cell layer" and furthest inside
"grain cell (granular) layer".