Access from:

- Freixo de Espada à Cinta (± 9 km) – Cabeço da Urca is W of this land and there are no signs to the top. Access only by dirt roads (only with jeep or TT).

GPS: 41.0955556, -6.8800000

It is the best known outcroping in Portugal of the cambrian - ordovician angular discordance. It is called discordance, because there are approximately 40 million years of deposits missing, and it is angular because the Cambrian and the Ordovician strata have different inclinations.

Cambrian – the word comes from the roman name of Wales, because this period was first established due to scientific research in rocks on North Wales. Is part of the Paleozoic era and is divided in Upper (520 to 500 million years) and Lower Cambrian (540 to 520 M). It is a geologic important period, because many groups of living beings appear then.

Ichnofossil or ichnite – from the Greek iknos meaning trace. In fact, it is a fossil trace of organisms’ activity that existed in the past (footprints, travel tracks, droppings, eggs and fossilized teeth marks are examples of ichnites).

Ordovician – period after the Cambric, from more or less 500 to 435 million years ago, known by the marine diversity.

Quartzite - metamorphic rock consisting largely of interlocking quartz grains.