Mary Augusta Greig was born in Hobart on 29 May 1845, the eldest daughter of Joseph Thomas Smales and his wife Mary Ann Roberts. From the age of six she took drawing lessons from Samuel Prout Hill and later from Robert Beauchamp. She was a member of the Launceston Art Society and Tasmanian Art Society. Two of her paintings received awards at the Tasmanian Exhibition in 1891-92. Her 'Tasmanian scene, River Ouse' was highly commended and 'Lake St Clair' won a second prize. Her works are held by Tasmanian art galleries.
On 6 Jan 1863 Mary Smales married Charles Grace Greig. Her sister Emma Elizabeth (born 1847) was a witness at the wedding. They had two sons and two daughters: John Percival, 1863-1881; Ethel Grace, 1865-1945; Florence Mary, 1866-1937; and Augustus Edward, 1868-1942. Her husband Charles died in 1897 leaving Mary a widow for 20 years. She continued her interest in art while living at 'Stratton Cottage', 94 York Street. Mary died on 26 Jun 1917 and was buried in the Scotch Cemetery in High Street, Launceston. See The Examiner 1 Apr 2006, p.30.