In doing research on Long Island history, I've come across some
 information on ear-marking, an early form of identifying cattle.
 Beginning in colonial times and up through the 1800's the townspeoples
 cattle and sheep were often pastured together on common lands.  The
 animals were left in charge of a keeper who watched over them and was
 paid a fee for his services.  He rounded up strays, rescued cattle who
 got stuck in the marsh or were injured, and herded them into enclosures
 when necessary.  Each owner identified his cattle by means of an
 ear-mark.  This was a similar system to brands that were used on Western
 cattle.  Earmarks were registered with the town clerks as evidence of
 private ownership.  Earmarks were cuts in the animals ear in a specific
 pattern.  They can be used as a source of information in tracing
 genealogies because a son would use the same ear-mark of his father
 after his fathers death.  Earmarks were recorded in the town clerk's
 offices by means of a diagram and in the larger offices, an accompanying
 written description.

Georgina Martorella
Newsday--Long Island History Project