Mary Garland Bullivant wrote under the name “Garland Bullivant”. She wrote two books, both beautifully illustrated: the first by Frank Hart and the second by Anne Bullen. They are both reasonably easy to find without their dustjackets, but much harder with. Little Lass is a good example of a pony biography: popular during the 1920s and 1930s, before it was superseded by stories focused on the rider.
Both Mary Garland Bullivant’s books were written before she was twenty. Mary Garland Bullivant is described on the dustjacket of the Country Life Junior Library edition as “a well-known rider in the West Country [and is] aged 15.” As with most of the very young pony book authors, she wrote stories of a pony’s life. Although some, like Primrose Cumming, Kathleen Herald (later K M Peyton) and the Pullein-Thompsons, carried on writing, most of these very young authors simply stopped once they were out of their teens.
Finding the books: both books are easy to find, and generally reasonably priced.