Map worlds : a history of women in cartography / Will C. van den Hoonaard. (OCLC #830352925)
This book on our shelf had the same call number as this book on a very different topic:
Sea monsters on medieval and Renaissance maps / Chet Van Duzer. (OCLC #844705228)
Both were classed under GA203, a general special class number (under Cartography–History) which is for special aspects of the subject as a whole which don’t have their own place in the classification. I moved the sea monsters book to GA781 (Cartography, European maps) which was more specific; the sea monsters aspect is still accessible via subject headings.
No new “general special” numbers are being established, and there are generally only narrow ways these classifications should be used (amorphous works, too new subjects). However, GA203 has a scope note specifying that it should be used for “cartographical sources, value of maps in boundary disputes, popes as geographers.” The topic “women cartographers” seemed similar in scope, and I couldn’t find a more specific appropriate classification, so I left it as general special.