My paternal grandfather's mother's name was Henrietta Margaret Adeline Davis-Violenes (this is the spelling I've run into time and again, but it wouldn't surprise me if it's spelled incorrectly).
She was born on StMaarten on 1839, day and month unknown, and passed away on 21 Feb 1900.
Could she be the same person as your Henriette Margarette Davis/Violenus?
I have her as being married to Peter John Labega on 18th Dec 1870. This would ave made her about 40 or 41 at the time.
I have her mother's name as Catharine Henli (or Henly) Davis, father's identity unknown.
Is it possible she married my great grandfather at a later date?