1850 Census, Whitley County, Indiana, dwelling 270, family 278, page 472a
James Joslin, 54, farmer, born L. C. [probably Lower Canada although it has been interpreted as South Carolina by some researchers]
Abigail, 46, born Ct [Connecticut]
Edwin, 20, farmer, Real Estate valued at $200, born O [Ohio]
Joseph, 17, farmer, Real Estate valued at $160, born O [Ohio]
Emily E., 12, born O [Ohio]
Mary L., 6, born Ia [Indiana]
Bela Goodrich, 74, born Ct [Connecticut]
Lysander Price Joslin was married on August 23, 1843 to Lydia Robinson. Their family is listed in the 1850 census on the page preceding that of James and Abigail.
1850 Census, Whitley County, Indiana, dwelling 262, family 270, page 471b
Lysander P. Joslin, 25, farmer, Real Estate valued at $350, born O [Ohio]
Lydia, 24, born O [Ohio]
Ann E., 5, born Ia [Indiana]
Melissa M., 11/12, born Ia [Indiana]
Fanny Joslin, the sixth 'child' of James and Abigail, was married to Joseph Shoemaker on February 5, 1843 and they were also living in Whitley County in 1850 (page 460).
While the 1850 census does not provide relationships to the head of household, the fact that James Joslin was the only 'Joslin' found in Whitley County in 1840 carries a certain amount of 'weight' indicating that he is the father of the children listed in his household in 1850 and he is really the only candidate to be the father of Lysander and Fanny as well.