Congratulations on finding the match. DNA testing has solved several tough genealogical issues for me.
Do you know how Marshall Morton is descended from Thomas or do you simply know that the descendant(s) of Thomas tested and your testee share a recent common ancestor? For example, there are 8 men surnamed Wright with matching DNAs in my group on the Wright Surname Project. These 8 men all share a recent common ancestor somewhere prior to say 1700, but these 8 men descend from four different immigrants who settled in four different states (colonies) in the mid-1700s. Before DNA testing we had no idea that we were related.
Is Marshall Morton and his wife within 5 generations of the person that is being tested? My understanding of the Family Finder test is that it is useful for finding cousins with common ancestors within the last 5 generations.
I checked the Morton Surname Project link at FamTreeDNA, but it looks like it is limited to only one or two immigrant families and doesn't include my Mortons.
I found only one match for your DNA test on ySearch and that was a Morton from Maryland. Ysearch has a test of one of my Morton cousins, but unfortunately only 12 markers were tested which is subject to numerous false positives and some false negatives.
You might consider changing your email address on genforum from "hidden" to the actual address. Since GenForum displays the email address in graphical format it is not available to spammer search engines. I limit my responses on GenForum when the email address is hidden.
You are welcome to email me direct if I can help or to compare information on our Mortons, but our Mortons match only 6 out of 12 markers at which point the assumptions and presuppositions used make the DNA statistical relationship analyses meaningless.