I believe all the Dalby's from Dalby Springs are related to Knight and Ann (BULLOCK) Dalby from Virginia and North Carolina via Tennessee. I have Hiram B. Dalby's ancestors back three generations to Knight and Ann. This information came from a book written by Norman Leonard Dalby entitled "The Dalby's of Northeast Texas". Here's a brief listing for you.

Knight and Ann Bullock Dalby
2 of their children (there were many others):
Phillip A. Dalby and James Bullock Dalby
Their children, Phillip A. II and Mollie, respectively, married. (They were first cousins as were Knight and Ann.)
Children of Phillip A. II and Mollie were:
Hiram B. "Bug", Harry, Lula, Ora, and Henry according to Mr. N. L. Dalby. Many of these people he knew personally or had heard of through the family. I have entered his book's family tree into my genealogy program, and I would be happy to send you a gedcom file. Another of Knight and Ann's children, Thomas D., stopped for a short time in Dalby Springs, and then continued southeast to Cherokee County where I grew up.