Jackson Clark, a leading authority on Navajo weaving and owner of Toh-Atin Gallery in Durango, will give two free lectures at Sorrel Sky Gallery on August 20 at 4 pm and on August 22 at 11:30 am. Clark, a founding member and former officer of the Indian Arts and Crafts Association and a past judge at Santa Fe Indian Market, has worked for decades to promote authentic Native American arts and crafts. A large collection of Navajo rugs, vintage and contemporary, from many different areas of the Navajo Reservation will be available through August 31.