A fossil should be labeled with as much information as possible, including the species or genus if known, the collecting location, rock unit, collector, and date collected. For the location, specify at least the city or county, and preferably the specific site as well, such as "Acme Strip Mine, Anyville, Ohio."

The rock unit normally refers to a formation, a sequence of rocks layers sharing certain features and usually deposited under similar conditions. Examples of formations are the Cleveland Shale and the Glen Rose Limestone. Geologists often subdivide formations into smaller units called members or beds. When the identity of a fossil is unknown, it is important to record at least the name of the formation and collecting locality.

Also helpful to include on a label, especially if the item will be displayed, is the geologic period of the host formation, such as Lower Cretaceous or Upper Jurassic. This allows others to know approximately how old the fossil is (based on the Geologic Time Table, discussed earlier). Information about geologic formations in an area and their geologic ages is found in publications and maps by the U.S. Geologic Survey and other academic works, including fossil collecting guidebooks. When collecting with a group, normally you will be given the name of the formation and its geologic age.

Rather than try to write all pertinent information on the fossil itself, most collectors and curators use labels or index cards, which are then affixed to the specimen, placed in the same container, or recorded in a notebook. Often an identification number is written on both the fossil and paper record (as a way of correlating them). ID numbers or other data can be written on a fossil by first applying a patch of white paint in an unimportant area, and then writing with India ink, black paint, or a permanent marker. Identification numbers used by museums and universities often start with the initials of the institution, followed by a number, assigned consecutively. Others use a code for the fossil group before the ID number. You may want to use one of these methods, or devise one of your own. If you have a computer, a database software package can be used for cataloging your fossils.

ID # _____________________________ 
Genus/species _________________________________   
Common name ___________________________________   
Period/Age ____________________________________  
Rock Unit _____________________________________  
Locality  _____________________________________   
Collector ____________________ Date ___________    
Notes _________________________________________  

Fossil identification card