Theophilus Cass, Jr. 1777-1861 (son of Simeon, but "Jr." to his Uncle Theophilus, brother of Simeon) married 12/18/1799 Jane McClary Sanborn 1778-1872, dau. of Eliphalet Sanborn (4) 1730-1794 and Margaret Wallace(5) 1743/44-1836. Margaret was the dau of Margaret McClary 1715-1761 and George Wallace, Sr. b. about 1719 d. before 5/20/1795 (Will proven).
Sarah/Sally S. Cass b. 1/27/1805 d. 3/25/1885, m. James Munroe Locke b. & d. Stanstead, 1804-1862.
Sophia Cass b. 12/12/1806 m. 3/14/1837 Pearson Libby b. 7/24/1806.
Both Sarah/Sally & Sophia dau.'s of Theophilus, Jr., one would think there should have been other children between the 12/18/1799 marriage date at Epsom and Sarah b. 1/27/1805.
If you have not seen this use of "Jr." (Jr. to an Uncle or other man of the same name), it was common in early NH. My Epsom ancestor John Yeaton, Jr. was the son of William Yeaton, Jr., BOTH men "Jr." to another William Yeaton in Epsom who was "Sr.", his son John was called "Sr.", and his (William Sr.'s) son William was called "3rd".