Col. John B. Clark's MO Infantry Regt was organized in Nov 1862. Companies A-C and H were formed from various MO company organizations, while Companies D-E, G and I were formed by the consolidation of the 8 companies of Clarkson's Cavalry Battalion. No record exists for Companies F or K.

By S.O. #171, Hqs Dist of Arkansas, Sept 30, 1863, Companies A-C and H were consolidated with the 8th MO Infantry Battalion (Musser's) to form the 9th MO Infantry Regiment, also commanded initially by Col. Clark.

Companies D-E, G and I, which were made up of Arkansans, became the 15th Arkansas Cavalry Battalion (Buster's).

Hope this helps some.