Mexico Silver Cobs
The Mexico City mint was the first to strike coins for Spain in the New World in 1536, starting with round issues under Charles-Joanna that are not technically cobs. Later, the mint changed to the shield-type design in the late 1500s, which became known worldwide as the reliable "piece of eight" currency during the 1600s and 1700s. The shield-type cob was phased out in 1732-1734, replaced by the machine-made "pillar dollars" after an experimental, hand-cut "klippe" type.