In the Oregon segment of the Cascade Volcanoes that runs for south of Mount Hood, there are at least 1,054 Quaternary volcanoes, which form a volcanic belt in width. This volcanic belt extends up to to the north of the border with California, where Quaternary volcanic activity is interrupted by a gap up to the Quaternary volcanoes near Mount Shasta. The Quaternary volcanoes within the Oregon Cascades are extremely dense, concentrated within an area of about . Rocks within the Metolius Springs area form part of the High Cascades province and include both volcanic and glaciofluvial deposits.