Name, year and place of birth and death from on-line research by Brian Oliver of nzolivers.com

Date and place of marriage from:
https://www.wikitree.com/wiki/Hewish-1

Day of birth, date and place of christening, from research file09 in May 2017.

A “Mary Ann Snow” was a witness at the wedding of “Emma Snow” to “Joseph Dodson”, as per Marriage Certificate received from New Zealand BDM on 18 September 2020. Was this “Mary Ann Snow” her mother? Emma’s sister “Mary Ann Snow” lived and died in England so perhaps not Emma’s sister?

The barque "London" Passenger Information for the "Snow" family found in March 2022:
http://www.museumnp.org.nz/early-settlers/voyageDetails.aspx?voyageid=10
Voyage Name: London
Tonnage: 388
Departure Port: Gravesend
Destination Port: Nelson
NZC Ref: 34/2, pp.276-88; 36/9
Examiner Ref: 16 April 1842, p.22
Voyage Information: Captain Joseph Gibson commander, J F Wilson surgeon superintendent.
Sailed from Gravesend 17 November 1841. Arrived Nelson 10 April 1842, emigrants landed 12 April.
Passengers on The Voyage:
Snow, William. Age on arrival: 38. Profession: agricultural labourer
Snow, Mary. Age on arrival: 39. Profession: wife
Snow, Edwin. Age on arrival: 14. Profession: tailor
Snow, Emma. Age on arrival: 11. Profession: child
Snow, William. Age on arrival: 10. Profession: child
Snow, Thomas. Age on arrival: 8. Profession: child
Snow, George. Age on arrival: 6. Profession: child
Snow, Mary Ann. Age on arrival: 3. Profession: child
Snow, John Henry. Age on arrival: NR. Profession: child
Snow, Sarah Rebecca. Age on arrival: 2. Profession: child

Date and place of Christianing confirmed in March 2022 from England, Select Births and Christenings:
Name: Mary Hewish
Gender: Female
Baptism Date: 26 May 1799
Baptism Place: Cheriton Fitzpaine, Devon, England
Father: Andrew Hewish
Mother: Rebecca

NOTE: Cheriton Fitzpaine is nine miles (15 km) north of the major city of Exeter and falls within the district council of Mid Devon.

Date and place of marriage confirmed from England, Select Marriages, 1538-1973, in March 2022:
Name: Mary Hewish
Gender: Female
Marriage Date: 31 Aug 1820
Marriage Place: Cheriton Fitzpaine, Devon, England
Spouse: William Snow

Result from death search on New Zealand BDM website in March 2022:
1884/5472. Snow, Mary. Died age 87Y

Full date of death of 13 July 1884 confirmed from further searching in March 2022 on BDM Search by incrementally changing the date range for the death.

Place of burial as “Wakapuaka Cemetery” and in daughter’s, Sarah Rebecca Moore (nee Snow), family plot. From cemetery records page 281 and 282 found in March 2022:
3715. Anglican Block 2, Plot 51:
MARY SNOW wife of the late William Snow, died 13th July 1884 aged 87 years