In his municipality have opportunity to observe the four geological eras in which scholars have divided the history of our planet. The Primary is represented in the western part of the term, on which he sits the town of El Vellon, and is part of the Massif metamorphic San Pedro, a plateau gneísica characterized by a relief and gently undulating hills between Vaguada.

Surrounding this enjoyable plain rises a broad arc that Elimite limestone to the north and east. They are formations of the secondary was giving a karstic landscape where caves abound (such as the Moral), the gorges (such as Quebraones) and quarrying of limestone and lime.

Going down the valley and along the riverbed of the Jarama, we found a field of boulders that make up the íltima of geological eras, the Quaternary.

Hydrological speaking the main artery of the river Jarama River is the town that just separated his term by the west Talamanca. All the rest of your network is formed by small river tributary streams that run in the previous drección east or southeast. They are noteworthy that the stream of Mount form majestic limestone cut to the north of the term, the sites of Los bartenders and Quebraones; Hocecilla of the stream that runs southeast deepening a beautiful and soft vaguada in the old massif metamorphic, and the stream of Saint Vincent or Malacuera reflecting the natural outlet of an ancient river that ran during the tertiary parallel to the current Lozoya and, after a series of catch basins, has led to the current river Manzanares and Guadalix.