The valleys formed by erosion have been hollowed out in the rocks by the strength of the water and bring to light geological events that took place during millions of years. Here the torrent hollowed out metamorphic rocks of Gneiss of Stabbiello and hornblende schists and epidotes, which were formed more than 280 million years ago. As at the 6th stop, we can see on the opposite side of the valley an area of contact between these two rocks.
The outcrop of Gneiss of Stabbiello along this path, often covered with earth and humus on the upper part where different species of ferns grow, is the ideal habitat for many invertebrates, which prefer the cool and humid microclima and where they shun the light. These animals play an important ecological role in the decomposition of organic material. They eat the debris of vegetation and animal origin and transform them into humus, rendering the soil fertile. The plants then reabsorb the substances produced by these organisms and transfer them into organic matter. To this category of animals belong the Diplopodans (commonly called millipedes), whose segments have two pairs of limbs, the Chilopodans (or centipedes), with segments with only one pair of limbs, and the Isopods (also called "woodlice"), which are crustaceans that have adapted themselves to life on dry land.
The Historical Sonvico Nature Trail
Stage 1: Well and "Riaron"
Stage 2: House of Reason
Stage 3: Graad
Stage 4: Cassinel
Stage 5: The mixed broadleaf woods
Stage 6: Geological oddities
Stage 7: Mill and bridge
Stage 8: The glade in the wood
Stage 9: The torrent Franscinone
Stage 10: Wash-house
Stage 11: The birds of the wood
Stage 12: Water and energy
Stage 13: The edge of the flood-level wood
Stage 14: Dairy farm for the processing of milk
Stage 15: Lime-kiln
Stage 16: The rural area
Stage 17: The Humid area of Canéed
Stage 18: The earth kiln for charcoal production
Stage 19: Terracing
Stage 20: Madonna d'Arla
Stage 21: The Chestnut Wood of Pian Piret
Stage 22: The Beechwood
Stage 23: The Boulder with Engraved Cupels
Stage 23: I Denti della Vecchia
Stage 24: R’Alborón
Stage 25: The Oratory of S. Martino
Stage 26: The old center of Sonvico
Stage 27: The Walnut Press
Stage 28: The Church of Saint John the Baptist
The Luganese Regional Bus Line covers the Lugano – Sonvico stretch; from Val Colla you can reach Sonvico, using the postal bus from Tesserete to Sonvico.