This may not be much help, but since Dorsey Allen is such a rare name I thought I would mention it.
My Gfather was Dorsey Allen b. 1849 in Fredericksburg, VA. He Married Carrie Criswell. They had a son Dorsey E. Allen that is unaccounted for from my records. Dorsey moved to Washington, DC with Carrie. Layton was a big name in Fredericksburg as well. FYI