iv, 27 pages : illustrations (some color), map ; 28 cm
OCLC
ocm47032081
Includes bibliographical references (pages 23-24).
Also available via Internet from the USGS Web site (PDF file only). Address as of 6-22-01: http://oregon.usgs.gov/pubs%5Fdir/WRIR01-4065/wri014065.pdf; current access is available via PURL.