Mavis Thorpe Clark (1909-1999)
Born as Mavis Rose Latham in Melbourne, Victoria in 1909. Another author to start early, having a serial published in a magazine by the age of 14 and a book which she wrote when 18 published a couple of years later. Quite a prolific writer, with 32 books published, mostly for children.
In researching one of her adult books, an important work on Sir Douglas Nicholls (an Aborigine who later become Governor of South Australia) she accumulated a huge wealth of information on the Aboriginal way of life.
So far I have only found one pony book written by her, but it is a corker - a real old-fashioned traditional pony story, although the main character is a boy.
She also wrote under the pen name of M. R. Clark