Donna, I assume you do not have the book 'Descendants of Philemon Dickerson and Captain John Dickenson' by Wesley Baker, 1978, 1979, and 1983. I have the 1979 book. We are of the same line but different brothers. The line is Philemon, Peter, Thomas, Daniel, Nathaniel, Nathaniel, Jr. Nathaniel,Jr md Mary Pool, had 10 children - Peter b 1806 (your line) and Ezra (my line). Baker does not show Mary Alice as a daughter of Abigail Maria (Dickerson) and George Niper. He does show in the section on Abigail's brother, William Cady, a reference to a Mary A, a niece, as Mrs. Whitfield Case of Dover NJ. Abigail Maria's siblings were John M, Maryann, and William Cady, none had children. Further review indiates Mary Alice is Abigail's daugher. I am confused about Mary Alice's married name. Is it Case or Beam?Was Mary Alice married twice? Baker's book indicates Abigail's children were sent to live with their grandmother, Phebe Dickerson, as per 1880 census because Abigail and George died. Can you give me information on your line? I live near Succasunna. Family Search.org is a good website.