I notice that the 1849 marriage notice says Mary is the third daughter of Thomas CAVE, this is also printed in the English press Tuesday, Feb. 26, 1850 Publication: Sherborne Mercury, although it says "Thomas Care".
(There is also a marriage announcement in England for Anne "third daughter of the late Charles Cave, Esq,. Stoke Parsonage" on 6 Sep 1852 - Saturday, Feb. 26, 1853 Publication: Western Times.)
The 1841 census for Charles at Stoke sub Hamdon Lower North St:
Charles CAVE 50 yeoman
Susannah 40
John 15
Elizabeth 15
Sarah 14
Ann 12
Martha 9
Jane 7
Lucy 5
Susan 3
HO 107/960/7 pg1
I wonder where Mary is?
Seems some confusion about names and place in the family?
Also an advertisement that may be of interest for "Prime Timber to be sold by Auction" at Stoke under Hamden on the Parsonage Farm, Mr Charles CAVE will appoint someone to show the Lots.
Saturday, Jan. 16, 1847 Publication: Sherborne Mercury
Modified to add:
I notice John TERRELL is a few pages away from the CAVE's on the 1841 census (pg 5)
Modified again:
This might be Mary in 1841 in Martock, with James (60, carpenter) and Rhoda (60) COURT
HO/107/951/2 pg 24