Kate who marries John Phillips in 1878 is the illegitimate daughter of Johanna (mispelled on the register as Joannah) who marries Thomas Yates in 1858. Some family histories have them as sisters who travelled out together from Cornwall, but Johannna did not have a sister of this name.

Thank you for your comment NebMaatRe.

This appears to be the birth and death for your Kate RETALLICK married to John PHILLIPS in Victoria in 1878.

BIRTH/BAPTISM.

Name: Catharine Burton RETALLICK.
Born: 30 May 1853.
Baptised: 29 October 1854, St Columb Major, Cornwall.
Father: Not recorded.
Mother: Joanna.

DEATH.

Nane: Kate PHILLIPS.
Died: 1937 Rutherglen, Victoria, Australia.
Age: 84 years.
Father: Edward Burston RETALLICK.
Mother: Joanna unknown.

If anyone has Kate's marriage certificate for 1878 they may be able to confirm Kate's parents named on the certificate.

Looking at the Cornwall and Australian records there is nothing to indicate Johanna and Kate were sisters.

Baptism and death for Joanna RETALLICK.

BAPTISM.

Name: Joanna RETALLICK.
Baptised 01 January 1837, St Columb Major, Cornwall.
Father: William.
Mother: Catherine.

DEATH.

Name: Johanna YATES.
Died: 1876 Victoria, Australia.
Age: 40 years.
Father: William RETALLICK.
Mother: Catherine unknown.

Kate names her parents as Edward Retallick, Storekeeper and Johanna Burton. A note from the celebrant indicates he has some doubts.

Since her mother is known to be Johanna Retallick, and illegitimate children were often given the purported father's surname as a middle name, it can be assumed the father may have actually been Edward Burton.

A likely candidate has been identified in Edward Joseph Burton (1826 to 1900), a second generation storekeeper in that area of Cornwall.

Johanna and Thomas' eldest daughter Elizabeth (my ancestor) is one of the witnesses on the certificate.