You can also collect the postmarks on envelopes, postcards, or other pieces of mail. These marks are interesting because they show when and where a piece of mail was posted. When a postmark is used to deface a stamp so that it cannot be used again, it is called a cancellation.

Bishop mark
This mark is the oldest postmark used by a postal administration. It is named after Colonel Henry Bishop, the Postmaster General of Great Britain, who introduced it in 1661.

Dockwra mark
Named after its inventor, William Dockwra, this mark was used in Great Britain between 1680 and 1682 to indicate that the postage for a piece of mail had been paid. It also recorded the exact hour when a piece of mail was posted.

Machine cancellations
These modern cancellations indicate where a piece of mail was posted as well as the date of posting, and have wavy or straight lines to cancel the stamp.

Bar cancels
These cancels consist of bars in rectangular, oval, or circular patterns. Such cancellations were widely used in Canada during the nineteenth century.

MCP 1974.1150.11 ; MCP 1975.1150.12 ;
MCP 1974.1154.1

Cachets
These designs are stamped onto letters to denote the special circumstances in which they were posted, such as the first flight of a new airmail route.

MCP 1974.1513.50 ; MCP 1974.1287.55

Circular postmarks
These marks consist of a single or double circle and indicate the date of posting.

MCP 1974.1000.343 ; MCP 1974.1000.320 ;
MCP 1974.1200.341

Commemorative cancels
These cancels, commonly found on first day covers, commemorate a special taking place on the date or at the place of cancellation, such as the issuing of a new stamp.

MCP 1974.1262.44 ; MCP 1974.1295.22

Directory marks
These marks explain why a piece of mail was not delivered.

MCP 1974.1172.3 ; MCP 1974.1159.6

Duplex cancels
These marks have two separate components: one that indicates the date of posting and another that cancels the stamp. Duplex cancels were used in Canada from the 1860s until the 1950s.

MCP 1974.998.91 ; MCP 1974.998.10

Instructional marks
These marks indicate special handling of mail in transit.

MCP 1974.1229.1 ; MCP 1990.12.10

Registered postmarks
These marks are stamped onto a piece of mail to indicate that it requires greater security in transport.

MCP 1974.1218.4 ; MCP 1974.1192.4