Who is Mrs. Brown from The Water Is Wide and what is their importance?

Mrs. Brown is the black woman who is the other teacher at the Yamacraw Elementary School. Pat describes her as, "A large woman, she had great pendulous bosoms and huge sinewy arms and a handsome, expressive face. She was light-skinned and laughed a great deal. Everything about her seemed exaggerated and blown out of proportion." Chapter 2, Page 23 Mrs. Brown is quick to inform people that she is very different from the black people on Yamacraw because she has Cherokee Indian blood and comes from Georgia where she was educated in a private school.