MAURITANIA (1975) Elephant*. Trial color proofs in full sheet of 25. Rock carvings. Scott No 330, Yvert No 335.
AVAILABLE AT $400
CHAD (1967) Rock paintings (masked dancers)*. Trial color proof pair. Scott No C38, Yvert No PA42.
AVAILABLE AT $12
SENEGAL (1967) Lyre-shaped megalith*. Trial color proof strip of 3. Scott No 295, Yvert No 300.
AVAILABLE AT $50