Rob,
Found one ....

February the 18, 1862
Missouri, Iron county, Missouri

Dear father and mother. I take my pen in hand to inform you that we are both well at present and I hope when these few lines comes to hand, they may find you all well.
I can inform you that our men has taken Fort Donalson and they took fifteen thousand prisoners and our men has taken Bo prisoner and all of his force, about eight thousand prisoners that was the telegraph displacement to Col. Carlin. I think that he will be mad before long.
Well, I haven't much to write this time. I received your letter an I was glad to hear from you. I would like to see you all mighty well and talk with you but it is so that I can't.
We are again to leave here in a few days and I don't know where we will go yet. I think we will go down towards Greenville.
Well I can inform you that Greenburg right has got back and he didn't fetch them things that you sent us. He left them at Saint Louis. He left them and we will get them when the mail comes and we will have to pay about one dollar. I have got a little money. Got thirty five dollars coming next payday besides what I will draw.
I want you to write as soon as you get this letter, some more at present.

John Thompson to Judy Ann Thompson, James Thompson, Joseph Thompson, Cathrin Thompson

Not sure how to read that, but it's the only reference I found to a Col. Carlin.........