Clemson William McCaslin married Elizabeth Mary Decker about 1837
Children:
Simeon Albertus (1838–1914)
Jacob Ennis (1840-1924) - 2 burial locations, Ref Civil War
Clemson/Clempson McCaslin (1843-before 1855)
Ruey Alvina (1844–1934)

Clemson William McCaslin married 2nd Eliza Ann Newman
Children:
Eliza Ann McCaslin McNeil (1845-)
William Rathbone McCaslin (1846-1921)
Joseph McCaslin (1847-1909)
Rosanna McCaslin Bliss (1848-1942)
Phoebe Jane McCaslin (1849-)
Mary McCaslin (1850-before1855)
Henrietta McCaslin (1853-1859)
Ella Lorana McCaslin Clark (1855-1946)
John William McCaslin (1856-1883)
Peter McCaslin (1861-1924)
George Frank McCaslin (1961-1939)
Catherine McCaslin (Caslin) Phelps (1862-1940)
Abram L. McCaslin (1866- after 1921) {some confusion on parentage of Abram, possibly a son of Phoebe}

Clemson William McCaslin married Amaranthia Champlin Morris before 1880:
1880 Census includes: Clemson Mc Caslin 62 Amarintha Mc Caslin 53 Note: Clemson's age of 62 specifically stated in this document coincides with a birth year of 1818.

Clemson William McCaslin married Mary Jaynes Babcock 1885
NYS Yates County Vital Records

Genealogy notes:
Of Note: Simeon Albertus McCaslin, son of Clemson William McCaslin and first wife Elizabeth Mary Decker, married his stepsister, Cynthia Fisk, daughter of Clemson's 2nd wife Eliza Ann Newman and Eliza Ann's 1st husband Otis Fisk.

Change in lineage: "John McCaslin #236230013" has been removed from previously thought to be parents of Clemson and Elizabeth Decker McCaslin. This John has most likely been confused with their son Jacob who was named as John in an early census record.

Clemson's life, wives and children are complicated to follow. This is the best information available to date and subject to change. Family Search has an additional wife and children named Lisa Scofield with no sources.