Published by the American Geophysical Union as part of the Field Trip Guidebooks Series, Volume 106.

This guidebook is for a six-day excursion between Issaquah, Washington (east of Seattle), and Portland, Oregon, that emphasizes the Tertiary and Quaternary volcanic geology of the western Columbia Plateau and the Cascade Range of southern Washington and northern Oregon (Figures 1 and 2). The guidebook summarizes the geology of selected areas along the route and provides a brief introduction to the general volcanic history of the Columbia River Basalt Group and the southern Washington Cascades. An extensive but not exhaustive bibliography accompanies the guidebook. The road logs are designed to be self-guiding; as such, they are more complete than necessary for guided bus excursions.