Hello Rena,
I am afraid I do not have much information on my Coburn side of the family. Let me get back to you in a few days however, as I took a trip to Northfield, Vermont last year and believe I saw a grave stone with the name (Alonzo Coburn) you are looking for. I do not know if it its the same person you search for but if it is, I believe this person to be a decendant of one William Coburn. You are welcome to write me direct if you wish. My e-mail address is: angie2253@mail.com
Best Wishes,
Angie