A political or administrative authority doesn't often happen to coincide with a geographical unit.
We're talking about the territorial coincidence between the "Comunità Montana Croce di Serra" and the Amerino mountains.
All settlements, from the main towns to the small hamlets are medieval. They were mostly built at an average altitude of 400 metres, at the boundary between an homogeneous rocky cover whose Mesozoic formation dates back to a period which goes from 180 to 50 million years ago, and the lower slopes, mostly argillaceous, of Pliocene age, dating back to only a few million years ago.
This homogeneity can be easily verified from the top of Mt. Croce di Serra, almost 1,000 metres high, with a breath-taking view which takes in a glance the Sibillini mountains at the east and the Cimini mountains at the south-west, up to reach the small towns perched halway up the hill around the Amerini mountains. From up there - where you can get on foot, starting from the pass crossed by the Montecchio-Melezzole road, on a clear day, especially in January or February, the snow clad peaks of Mt. Vettore and Mt. Terminillo, the hill of Todi and the rock of Orvieto will appear in all their splendour. If you are lucky you might even see a small bit of the Tyrrhenian Sea.
The cambered shape doesn't caracterize only the top of Mt. Croce di Serra, but the whole ridge between Guardea and Santa Restituta, easy of access, providing you wear heavy boots, because only in that stretch, the wooded mantle which covers the rest of the hilly and mountainous territory, is absent. This ridge is also a kind of wall separating a mediterranean subtropical microclimate southwards from the one typically continental northwards.
All this conditioned the diversification of the plants growing on both sides.
Southwards, from Amelia to Civitella del Lago there is one of the largest and most integral mediterranean bush of Centre Italy.