Searching for information on Mercedes Elena Diaz de Contreras (b. ca 1830) or her husband Emilio Diaz (b. 1835). There are records of 2 of their children, Maria Elena and David Washington Teodoro, born in 1888 and 1889, respectively, in online Chilean baptism records. They were each born in Santiago and baptized at Iglesia San Isidro.
I have seen each listed elsewhere as Emilio Diaz Gallegos and Mercedes Diaz de Contreras Alvarez, but have no hard sources to verify that these are indeed the people I'm looking for.