The sitter was Augusta Jones and this was probably drawn in the mid 1860's when she often sat for him. This seems to be a sketch related to his watercolour Astrologia.
Astrologia is depicted with her profile looking left. Augusta and her sister Milly were popular models in the 1860s, they sat for many artists including Albert Moore, Edward Poynter and James McNeil Whistler. The sisters features were ideal for representing the then current taste for neo-classicism, and their popularity is an example of the close-knit Aesthetic community.