Interesting that it could be alleged who the father was on the birth information, presumably without his permission?
The trouble with tracing the child is that she may still be living.Myrtle may be the Myrtle Ethel Sanders who married Louis Mortimer Mounce in Gila County, AZ in 1926 (license date 9 November 1926). Both were resident at Copper Hill. They went on to have children together. In the 1930 census they have two sons of the marriage with them but not a girl born before the marriage.