Henderson E. VanSurdam (Harry/Dutch) was a remarkable guy. He is in the College Football Hall of Fame and the Founder of University of Texas El Paso (UTEP) You can see his bio at the Hoosick Falls History website. (www.hoosickhistory.com) His great grandparents were Anthony Surdam and Lu Fanny Cronkhite. This Anthony is my wifes g-g-g grandfather from his second wife Sarah Smith. She was the widow of William Dunk and had a young daughter,MaryAnn and an even younger son William Henry. William Henry was about 2 years when they married and changed his last name from Dunk to Surdam. Anthony had 9 daughters and 3 sons with his first wife. One of the sons was named Walter who is HE Surdams great grandfather. The other two sons were Morgan and Henderson. This Henderson died between 1850 and 1860 leaving a wife and 3 young daughters.
I believe the Munson lady was his second wife. There are Texas records of a HE Surdam divorce. I have no knowledge if he had children.
There really is no distinction between Surdam and VanSurdam. It seems to have been used arbitrarily. Sometimes a junior would use it to separate him from his father. Sometimes the oldest son would use the Van prefix. Census takers would spell the name Suydam which is a Dutch method variation.
From my research it seems that the Surdam line was blessed with good health, longevity, luck and fertility. In times of plagues, warfare and adolescent medicine, they survived better than most families. Their only deficiency is the general lack of interest in their own genealogy. Hoosick Falls has a large number of Surdam/VanSurdam decendents but they don't add much to the database.