Ochoco Mountains made of rocks from the Permian, Triassic, and Jurassic periods (300 to 200 million years old) that were transported by the Pacific Plate and accreted in the late Mesozoic era (about 100 million years ago) as part of a vast shallow sea, then slowly uplifted by volcanic eruptions during the Eocene epoch (50 to 37 million years ago) to form the Clarno Formation. From 37 to 17 million years ago, eruptions in the western Cascade Range spread ash across eastern Oregon, forming the John Day Formation. From 17 to 14 million years ago, major volcanic eruptions covered much of the
St Brides Major (community) St Brides Major, the Dunraven estate and Clemenstone Meadow SSSI. Much of the coastline of the community is designated as the Southerndown Coast SSSI, both for its geology and botanic value. The stretch of shore, cliff, cliff-top, and several short, steep valleys, reveal the local geological strata. Carboniferous Limestone from upwards of 300 million years ago lies at the present sea level. By the Triassic period, 200 million years ago, these rocks were already tilted and eroded. A new deposition phase created more sedimentary rocks, including a red Triassic conglomerate, and a creamy white Jurassic limestone known as Sutton Stone,