Central Oregon Coast Region

The board's chain of volcanic islands is an older reading of the Coast Range. In 1982 the geologist Robert Duncan described it as a captured island chain; geologists now mostly describe a single oceanic plateau, basalt twenty to thirty kilometers thick that erupted on the seafloor between about 56 and 50 million years ago and was jammed against North America by 50 million. It is called Siletzia, a name coined in 1979 from the Siletz River and the reservation, and its pillow lavas surface in the range. A USGS team has argued its source was the Yellowstone hotspot.

Where it stands

More markers nearby

• Yaquina Bay — 22 mi