Once selected, each card is given an eight alphanumeric accession
number that identifies the subcollection, card number (a total of
9999 entries are available) in that series, the type of image (access
or archival), and whether or not it is a front or back view. Early on
in the project it was realized that having a related but unique
identifier for each side was vital to having both sides of a card
displayed together. At this point the Waterways series identifiers
are: Champlain (c), Erie (e), Delaware and Hudson (d), Hudson
River (h), and Seneca (s). Thus, a card in the Hudson River series