Mid-century Black modernist one eye clay vessel with feather accent, sign swirl S or E?

Black modernist one eye clay vessel with feather accent, sign swirl S or E? Measures around 9-3/4" by 5-3/4" wide. I am looking for help in recognizing the swirl signature. I had look through the Native American artists signature search and visual search without result. I would appreciate any information. Is it a wood fired clay? Geraldino Shapiro has similar work but she does signs her work with her name not a swirl. Any help?