Thought to be Ada Morris. It has on the back "My Mother age 18" and was with the Barber family photographs. The photographer, H J Spink, died in 1892 when Ada would have been 18 years old, and the photo is from the 1890s period. This type of photograph is called a "midget carte" and was the smallest format available for a commercial portrait. It was introduced in the 1880s but did not become widely popular until the 1890s.