There is a cemetery in Stuyvesant Falls, NY where there are a number of VanValkenburg's buried.One plot appears to have two families - Part of it is John Leggett VV (wife Jane Hoes) and his children, also his son Martin's children. Additionally there are other Van Valkenburgs who appear to exemplify the VV/Sharp confusion.
There are two markers for Barent VV - one without a date. Next to that is Elizabeth Sharp, wife of James VV, died 5-9-1844.
Then there are a few markers for children, three of which it indicates are the children of James and Elizabeth.
Catherine, died 6-27-16, age 13 Ann, died 12-22-1816, age 22yrs, 8 months, 2 days Barent, died 8-11-1849, in his 30th year
There is one other marker which says Catherine Ann, daughter of James and (I think) Heltje.
Barent's marker is the clearest of all the childrens. Baptismal records can be found on rootsweb for James and Elizabeth Sharp for Barent. He was born 1/2/1819, bp. 2/28/1819. So in 1849 he would be in his 3-th year.
Other children for which baptismal records exist are: Andrew, b. 12/01/1820, bp 1/14/1821 Hannah, b. 04/20/1823; bp 6/30/1823 Dorothy, b. 7/27/1825, bp 10/28/1825 Christina, b. 1/15/1828, bp 10/04/1833
Elizabeth Sharp could possibly be the daughter of Louwrens and Eliezabeth Ree
Bartholomeus VV (595) married a Helletje Scharp, They were married in 1765; Their children were Lambert (1767), Jacob (1769), Abraham (1774), Elizabeth (1777) and Margarita (1782).Helletje Sharp could be the daughter of either Jacob Sharp and Elizabeth VanDyck bp 8-14-1750 or the wife of Kasparus Hallenbeck or the daugher of Andrias Sharp and Elizabeth Goewey.
The VV Book 1 has some notes regarding this mystery