Thank you for submitting your item for appraisal. This appears to be a high quality charcoal drawing by Sandy Wynveen depicting a Native American Indian surrounded by wolves, riders on horseback and his spirit animal. Unfortunately the artist is not listed. She might have been active in the 1970s and I assume got married and changed her name, which makes it impossible to trace further information. The estimate is based on similar drawings by the artist sold at auction. There is no measurement for the sentimental value you might attach to the item.