ART OF ANGOLA, CAMEROON AND GABON, Part III of Selections from the Permanent Collection, at the Museum of African Art, 316-332 A Street NE, opens Friday, continuing indefinitely. Weekdays, 11 to 5; weekends, noon to 5. NIGERIAN WORKSHOP will examine the logistics of living and traveling in Nigeria and the cross-cultural impact on artists and their craft. Corcoran Gallery's Hammer Auditorium, Saturday at 1.

Ceramic, ivory, bronze and stone pieces recently unearthed in Nigeria make up a major exhibition of African art at the Corcoran. The show, "Treasures of Ancient Nigeria: Legacy of 2000 Years," is considered historically as well as esthetically important, correcting the misconception that Africa's more recent wooden sculptures are its primary works.

The 100 pieces, uncluttered and elegantly displayed in glass cases, represent several cultures. Nok terra cotta sculptures, Igbo-Ukwu and Benin bronzes (including a pair of leopards that decorated the King's altar, mid-16th century), an Ikom monolith carved from a boulder and Esie soapstone figures are presented simply, in this joint effort of the Smithsonian, the Corcoran and the Museum of African Art.

At the Museum of African Art itself, traditional art from Angola, Cameroon and Gabon is on view in an intimate upstairs gallery. An array of masks, headdresses and wood-carvings display what director Warren Robbins calls the "strong classical style" of a number of African peoples. Often, he says, the sculpture should be viewed as a vehicle for transmitting philosophy, religious or ceremonial customs, or moral and legal codes. Perhaps the show's most striking examples are a royal ancestor figure by the Bamileke people of Cameroon and a pair of elephant masks, one beaded and one carved wood, symbolizing the power of society. TREASURES OF ANCIENT NIGERIA, Legacy of 2000 Years, at the Corcoran Gallery of Art, 17th & New York Avenue NW., through February 1. Tuesday through Sunday, 10 to 4:30; Thursday evenings until 9.