The 1841 12 lb Mountian Howitzer was a favored weapon of both Union primarily and Confederate Cavalry units because of its light wieght and ease of movement for Cavalry movements and yet having a large enought shell to do considerable damage.

The 5th kansas Cavalry (US) had 6 of them and lost two at the Battle of Marks Mill, April 1863, those guns may have accompied Prices Missouri Raid (1864) and that may account for the gun being abandoned in a Swamp in Northeast Arkansas, Confederate records keeping being what they were at that period of time. Just Guessing on That.

This "find" is most unusual and it would be interesting to know the details since records of artillery were usually very well kept and the lose of such a gun was a major incident. I am not saying that unrecorded loses of such a weapon did not happen, but they are unusual since they were easy to account for, either you had a cannon or you did not.

Would love to see it, or a Picture.