It looks like Jacob's parents are John Collins(b.about 1805 VA or MD) and Emily Jane Goble/Gobble (b. about 1826 VA).Their marriage consent is listed in Floyd Co., KY with a date of consent of 8 Jan 1846.
Looking at the censuses for the couple they had the following children: 1.Alsey J.(female) born about 1847 2.Jacob B. 3.James A. born about 1855 4.Sylvester born about 1859 5.Arminta (female) born about 1864
On the 1880 census John and Emily are living next door to Jacob and Mary. Living with Jacob and Mary are Mary's mother Mary A. and her brother Hudson.
Mary P. Justice's parents were William Justice (b.about 1821 KY) and Mary A. (b.about 1818 KY)
In the 1870 census Jacob and Mary are living next door to William and Mary Justice.