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© 2025 Portland State University and the Oregon Historical Society

The Oregon Historical Society is a 501(c)(3) non-profit organization. Federal Tax ID 93-0391599

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clinker

In geology, chunks of solidified lava that float on top of flowing lava.

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© 2025 Portland State University and the Oregon Historical Society

The Oregon Historical Society is a 501(c)(3) non-profit organization. Federal Tax ID 93-0391599

© 2025 Portland State University and the Oregon Historical Society

The Oregon Historical Society is a 501(c)(3) non-profit organization. Federal Tax ID 93-0391599

.