\\ onian topreside at \lt;;\i sessionsOMAHA. Neb (ARi — Representatives of the nation's Indian tribes gathered Monday for the 25th annual convention of the National Congress of American IndiansThere was a last - minute switch in the presiding officer. Mrs. Georgeann Robinson ofBartlesville, Okla., will preside for the association president, Wendell Chino of the Mescalero Apache Tribe in New Mexico, who was unabte to attend be cause of ill healthMrs Robinson is first vice president An association spokesman said it was most unusual for a woman to preside at an Indian meetingThe first general meeting of the convention is set for Tuesday morning