Cherry Valance (Cherry) and Marcia. They are Socs. I know this because as Ponyboy thinks, "those two girls weren't our kind. They were good-looking girls- dressed sharp and really good looking."
They also call Ponyboy and his buddies "Greasers".
The new characters that are introduced are Cherry Valance and Marcia. They are socs because Ponyboy said that they are nice-looking girls and they are well dressed and that they weren't greasers. Ponyboy is a greaser, How you know this is that her and her friend called them greasers and all the socs call them grasers.