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I doubt that this will help, but I have in my database a Mary S. Vandivier b. Oct. 19, 1862, married to James Willan Ragsdale, d. 1931. I have Mary's father as Peter P. Vandivier and her sister as Barbara Catherine Vandivier, b.March 6, 1855, married to Harvey Walter Ragsdale, d. 1943. These Ragsdales are related to my ancestor, Frederick G. Ragsdale of Johnson County IN. I do not have a complete list of Peter Vandivier's children, but Mary and Barbara might be about the right age to be siblings of your William Henry Vandivier. The 1850 and 1860 census records might give you your answer.