Spade Guinea Pubblico Deposited
The name given to a variety of the Guinea issued in the reign of George III from 1787 to 1799, inclusive, on account of the shovel-shaped shield on the reverse, which bears a resemblance to an old-fashioned spade, or to the spades in a pack of playing cards. The half spade Guineas are of similar design.
- Frey's Dictionary (American Journal of Numismatics, Vol. 50, 1916)