This might nail it down:

HDQRS. MILITARY DIVISION OF WEST MISSISSIPPI,
Natchez, Miss., June 6, 1864.
First Lieut. I. N. EARL,
Co. D, Fourth Wisconsin Cav., Baton Rouge, La.:
SIR: The commanding general authorizes you to organize a corps of mounted citizen scouts for service in this division. They must be reliable men and specially fitted for this kind of service. They will be paid at rates ranging from $10 to $60 per month, according to the value of their services, and one ration each. They will be organized into squads, and their services accepted on the special condition that they will be held subject to strict military discipline and all the Rules and Articles of War.
Written engagements to that effect will be entered into with each man. Commanders of squads will be allowed increased pay in proportion to the importance of their commands. In cases where extra danger is incurred in the line of duty, or where specially valuable service is performed, extra compensation may be expected. If you know of any soldiers who are fitted for this duty they may be ordered to report to you at Natchez, Miss., when furloughs will be granted to them, with the understanding that they are not to draw any pay from their companies while employed on this duty.
Very respectfully, your obedient servant,
C. T. CHRISTENSEN,
Major, Assistant Adjutant-General.

OR1-V34-4, p. 243

George Martin