1850 Polk, Iowa Jones, Mary 39 PA William 20 PA Aaron 15 OH Sarah 13 IN John 10 IN Robert 8 IN David 2 IA
1850 Polk County Mortality Schedule Joseph Jones b. 1805 PA died May 1850 Congestion
1856 Polk, IA Jones, Mary 44 PA widow in Iowa 10 yrs Aaron B. 10 OH Elizabeth 18 IN (Sarah) John R. 14 IN Robert S 12 IN David 8 IA Ira G 5 IA (Mary was pregnant when Joseph died)
Robert Samuel Jones b. 1843 died 11/27 or 11/29/1914 buried Glendale Cemetery, Des Moines, Polk, IA Pvt Co. E 4th IA Cav-Civil War
William Jones, b. 1830 Fayette Co. PA settled in Story Co. IA. Died there in 1894.Story County Genweb site has many references and excellent indexing and search engines. It appears that many family trees on Ancestry have him tied to the wrong father and siblings.
Looks like Joseph and Mary were in Fayette, PA in 1830 and Vermilion Co. Indiana in 1840.