My mother, Edith S. Wessler, "collected" Joslins and I have her records.In 1957 she received info on this family from a genealogist in their line.I have no info for the 20th century for George Henry and Eunice and their three children, but perhaps a descendant from one of his siblings may be interested in the Bible you have.
George Henry Joslin, b. 27 Jan 1819, Surry NH, d. 26 Aug 1892, Rockford IL m. 3 Dec 1842, in Ulster PA, Eunice A. Olmstead, b. 9 May 1822, Sidney Plains NY, d. 11 Sep 1881, Durand IL.Their children were Henry, Julia E. and Nellie Eunice. 1. Henry, b. 29 Aug 1843, Towanda PA, d. 15 Jan 1909, Ulster PA; m. (1) Nellie Hall, b. 1843, Rockford IL; m.(2) before June 1880, Belle K Walker, b. 1856 PA. 2. Julia E, b. 12 Oct 1846, Rockford IL, d. 16 Oct 1947, Seattle WA.She m. 25 Dec 1867 in Rockford IL, Martin Sarver, b. 23 Dec 1842, Bedford Co. PA, d. 28 Jun 1908, Seattle WA.Their children were Dwight, Louise and Browny. 3. Nellie Eunice b. 7 Dec 1860, Harrison IL, d. 29 Dec 1894, Milwaukee WI; m. 13 Sep 1881 in Winnebago Co. IL, Charles Edwin Grout, b. May 1858, d. after 1900 when he lived in Milwaukee WI.
George Henry was second child, s/o Peter H. Joslin and Kerenhappuch "Katy" Sawyer s/o Peter Joslin and Sarah Kidder s/o Peter Joslin/Joyslin and Elizabeth Greenleaf s/o Ensign Peter Joslin and Alice Woods s/o Capt. Peter Joslin and Joanna Whitcomb s/o Nathaniel Joslin and Sarah King s/o Thomas Josselyn and Rebecca Jude, our mutual ancestors who arrived in 1635 from England.