Re the Baptism for Mary Ann SMITH at St Johns C of E 1815...
Mary Ann born Mar/1815, Bapt 14/05/1815
Rev Samuel MARSDEN's register can be quite helpful
look at the entry immediately before and the one immediately after the one for Mary Ann's baptism, and at the entire page as one image.
So there's Elizabeth, daughter of Stephen Parker and Harriet his wife, and in the margin he has also written 7 Hills....
Then there's Mary Ann Daugher of William Smith and Sarah his Wife, was born March 1815 and Christened May 14, 1815, Registered Same day by me Samuel Marsden ... (nothing in margin)
Then there's Isaac, son of William Barran and Ann Huby was born 1 Nov 1814 and Christened May 14, 1815 .....
Notice
* that Samuel Marsden wrote his entries up on the same day he conducted those ceremonies... so are likely to be reliable info.
* that Samuel Marsden could not establish that Isaac's mum and dad were formally married to each other
* notice that Samuel Marsden was convinced that Elizabeth's mum and dad were formally married to each other
* notice that Samuel Marsden was convinced that Mary Ann's mum and dad were formally married to each other.
* notice that Samuel Marsden recorded 7 Hills .... as in Seven Hills district ... but did NOT record a locality for most on that page ... so likely they were locals to St Johns C of E...
* notice further down the page is a baptism and a margin note 'Parramatta'
* remember that Samuel Marsden was one of the NSW Chaplains, and therefore was required to receive transmitted records of baptisms, marriages, burials conducted by other clergy (and not just by C of E clergy either) and record them in his registers as per one of the General Orders issued by the then NSW governor, Lachlan Macquarie... So Samuel Marsden would have reliable records showing marriages conducted by a) himself b) other C of E clergy c) other clergy.
* Samuel Marsden was one of the clergy who declined to marry couples if they had a prior marriage ... despite Lachlan Macquarie being very concerned about cohabitation...
So, the lass born March 1815, baptised 14 May 1815 was perhaps local to St Johns C of E, and her parents were a married couple, but as to her mum's nee name ... sorry, it may not be noted anywhere. She may have been baptised 7 Hills, or perhaps not...
Trove :
https://trove.nla.gov.au/newspaper/article/627934 Sydney Gaz 24 Feb 1810
https://trove.nla.gov.au/newspaper/article/628068 Sydney Gaz 15 Sept 1810
https://trove.nla.gov.au/newspaper/article/628150 Sydney Gaz 22 Dec 1810
JM