This is a Grenada OHMS Cover.  It was sent to the Cleveland, Ohio on 8/16/1900.

What makes this cover interesting is the OFFICIAL PAID HANDSTAMP CIRCLE in Black.  It also is endorsed on the lower left with an M/S G.P.O. GRENADA, and there is a Cleveland Receiver mark on the back. 

Included with this lot is a copy of a 1972 article in the British Caribbean Philatelic Journal by W. Danforth Walker.