- Usually come in sets, with the class portion of the call number typically ending in the numeral "0"
- Symbols may denote quarries, forests, archaeological sites, "ruins," etc.
- Show human culture (towns, some structures, modern roadways)
- Show rivers and streams
- Contour lines indicate elevation (labeled with number) and slope (spacing of lines: closer together is steeper)
- The main class portion of the call number (1st line) typically ends in the numeral "1"
- An alphanumeric code, usually on the 2nd line of the call number, indicates the primary subject of the map
||Alphanumeric code begins:
Mines and Mineral Resources
- Subject code .C5
- Bedrock geology shows solid bedrock often under the surface; "Surficial" or "Quaternary" geology represents recent sediments on top of the bedrock.
- A simple and fairly generic legend.
- Detailed standards for symbols on geologic maps.
If there's nothing for the area you're studying, then look for sets of maps covering any larger area that encompasses it. For instance, for detailed areas in Mali, look for sets covering West Africa or Africa or the world, not just for a single country.