Hi, all:

I think I've stumbled into a possible adoption situation.

Thomas, Priscilla and Cornelius DARLING were all born 1848-1853.
Thomas and Priscilla's wedding records record their parents as John and Priscilla DARLING
Priscilla was married at the residence of Samuel HAIGHT.
I have many records for Samuel and his wife Phoebe MILLS, including a census with the above listed under DARLING. This makes me think they were adopted and kept their own surname.
Priscilla married a Mr. TEETZEL, whose name shows up later in my line, so I believe this is the right Priscilla.
Another later relative has the middle name HAIGT, so I believe it didn't just come out of thin air, but was based on a relationship.
I carry my own grandmother's adoptive family's name, in fact, so it could have happened.

How would I begin to investigate a long-ago adoption? It's possible they were taken into the Haight home but not formally adopted, either. Any ideas? Thanks in advance!