vi, 49 pages, A29 pages : color illustrations, color maps ; 28 cm
OCLC
ocm57483696
Includes bibliographical references (page 47, 49).
Also available via Internet from the USGS web site. Address as of 9/30/09: http://pubs.usgs.gov/sir/2004/5133/pdf/sir2004_5133_lewelling.pdf; current access is available via PURL.