http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Issued in quadrangles 1⁰ of latitude by 1⁰30ʹ of longitude.
Relief shown variously by form lines, hachures, and shading.
Each sheet includes "Glossary," "Location diagram," and "Reliability diagram."
Accompanied by index map on 2 sheets 27 x 41 cm.