Sheila Gertrude Mackie ( 1928 - 2010 ) was a painter. Sheila Gertrude Mackie s works have been put up for auction numerous times, with realized prices varying from 13.98 USD for CELTIC HORSES in 2016 to 338.89 USD for A fox discovering an elf among woodland fungi in 2016 , based on the size and medium of the artwork.