This might be your Mary:

Quarter Sessions:
1834, Hill Mary, U, Bristol St.Pet, Q/Gc5/5, labourer, Gaol

If this is your Mary Hill it looks like she was of Bristol St. Peter (not included in the IGI).

Overseers Report:
1834, Hill Mary, C, P198a OV 3/2/16, Overseers

Same year and reference there are 3 other Hill´s:

1834 Hill John, C, P198a OV 3/2/16, Overseers
1834 Hill Eliza, C, P198a OV 3/2/16, Overseers
1834 Hill Henry, C, P198a OV 3/2/16, Overseers

Informations are from Gloucestershire Records Office, Genealogical Database.

You could try and contact Gloucestershire Records Office at this link:

http://www.gloucestershire.gov.uk/index.cfm?articleid=17142&...

Regards
Egdal