Natural Environment

Mutriku boats a natural environment unlike any other due to its location between the sea and the mountains.

This environment is also known for its great geological significance, since most of its coastline is formed by flysch and much of its environment portrays a very characteristic geological morphology known as karst.

The Flysch Landscape

The steep west coast of Gipuzkoa has a magnificent geological treasure. Millions of years of geological history are aligned in a long sequence of rock strata called flysch.



Karst
Mutriku offers various wonderful locations for naturalists, such as the Astigarrabia Valley, or the localities of Laranga and Galdonamendi. However, the more interesting points are undoubtedly Monte Arno and its surroundings and the Olatz Valley.o.

The flysch of Mutriku is known as Black Flysch, created more than 110 million years ago. It is one of the few places in the world where giant ammonites can be found. In fact, one of the most important fossils collections in the world has been gathered from here. This collection that can be visited at the Nautilus Geological Interpretation Centre of Mutriku.

This coastline has become a reference point for Basque palaeontology and geology. In fact, Mutriku is part of the Geopark along the Basque Coast, offering the possibility of unveiling all the secrets of the Mutriku coast while participating on its guided tours.

Find out more: www.geoparkea.com

The Karst Landscape

Mutriku offers various wonderful locations for naturalists, such as the Astigarrabia Valley, or the localities of Laranga and Galdonamendi. However, the more interesting points are undoubtedly Monte Arno and its surroundings and the Olatz Valley.

The Arno Mountain Range:

Arno is a calcareous mountain range with breathtaking landscapes. So much so that it has been listed on the European Natura 2000, and in 2013 it was declared a special area of conservation (KBG/ZEC).

Above all else, it was given this status due to the flora of the area and, more specifically, to the holm oak trees (Quercus Ilex) that are found across these mountains, being one of the most important holm oak forests in the north of the Iberian Peninsula.

The Olatz Valley

This beautiful valley is hemmed in by the foothills of Mount Arno and covers an area of about 2 km. Despite being very close to the coast, it is an eminently rural valley with a deep-rooted “baserritarra” (farmer) culture that depends mostly on tending to livestock.  Within this environment is the periphery of Mutriku, with the townships of Ondarroa and Marquina, and this is also where the Camino de Santiago passes through.  It has become a resting place for the stage between Mutriku and Marquina. 
 
As for the geology of the area, this is one of the most important environments within the Geopark along the Basque Coast. This is not actually a valley as such, but rather a Polje, which is a geological formation creating a valley through the erosion of the karst rock. The waters of this valley do not reach the sea directly, they disappear through very specific locations, which has given rise to myths and legends in the past. It was said that these waters were kidnapped by local witches in the numerous caves around the area. One key location is the Kobalde Cave, which is located just behind the Hermitage of San Isidro. This river disappears at this point to cross through the entire Arno mountain range underground and reappear once more in the hamlet of Astigarrabia and then finally flows into the Deba River.
Anyone wanting to see this landscape for themselves can take a 6.5 km geo-route where interesting elements of local ethnography can be seen, such as stelae, lime stones, mythological blocks, etc. There is information signposting along the entire route and, of course, visitors cannot pass through without tasting the delicious cheeses of the Goienetxe Homestead.
 
You can also find guided tours to see the valley for yourself on the website: www.geoparkea.com