One thought might be that the Capt. Kelly in question was Capt. E.V. Kelly. Consider the following....
"As soon as the Governor learned that the arms with which he had been hoping to equip the State troops had been removed from the arsenal, he directed General Harding, the Quartermaster General, to proceed to St. Louis, and procure for the State all the arms and ammunition that he could find in that city. That officer had in February reported to the Governor that the only munitions of war which the State owned, except a few muskets in the hands of the militia, were two 6-pounder guns, without limbers or caissons; about one thou- sand muskets; forty sabres; and fifty-eight swords. The latter were, he said, of an antique Roman pattern and 'would not be as useful in war as so many bars of soap.' In St. Louis he now purchased, partly by force, several hundred hunting rifles, some camp and garrison equipage, and about seventy tons of gunpowder; all which were shipped to Jefferson City on the 7th of May under guard of Captain Kelly's company, detailed for that duty by General Frost."
Snead, Thomas Lowndes, "The Fight for Missouri, From the Election of Lincoln to the Death of Lyon" (1886) pp. 362-63
"Captain A. A. Lesueur.
Captain Lesueur was born in St. Louis in 1842. At the age of eighteen he entered the State Guard service at Camp Jackson, in Captain Kelly's company. Two days before the camp was captured by Lyon, this company had been ordered to Jefferson City to guard the undistributed portion of the 120 tons of powder which had been stored there. His company, therefore, was not captured, and was probably the very first company in the State on duty after hostilities actually began. The company became part of General Parsons' division of Price's army soon after the Boonville affair."
Webb, William L. "Battles and Biographies of Missourians" 1900 pp. 364-65
"Before the battle of Booneville, and just previous to the abandonment of Jefferson City by Gov. Jackson with the state troops and government, 12,000 kegs of gunpowder were sent off from the capital to Booneville by boat, and from there scattered in wagons through the counties of Cooper, Saline, etc., and there secreted by a detachment under Capt. Kelly of the State Guards.... As an instance — ex-Senator Parsons, of Miami, successfully concealed about thirty kegs, of this powder in his hog-pen.... At the battle of Lexington much of this powder was used....
"History of Saline County, Missouri" pp. 280-81
LIEUT.-COL. BOYD'S OFFICIAL REPORT.
CAMP AT LEXINGTON MO September 22, 1861.
Lt. Col. D. W. FLOWERREL, Acting Ass't Adj. General,
Permit me to make the following report of the part sustained by the forces under my command in the battle of Lexington on the 20th inst. My command, consisting of six companies of cavalry, dismounted, under Captains Wells, Gibson, Robinson, Bostic, Bennett, and Lieutenant Moore, three companies of infantry, Captains Minter. Smith, Stout, and three pieces of artillery under Capt. E. V. Kelley, numbering in all 400 men, were stationed on the morning of the 19th inst. in and around the court house yard. At eight o'clock A. M. on the 20th inst., Captain Kelley was ordered with the battery to take position opposite northwest face of the enemy's entrenchments, and opened fire at a quarter past nine, within about 100 yards of same, which was kept up during the remainder of the day with the most telling effect, silencing one of their guns at the fifth round, which resumed fire in a short time and was silenced again at several intervals during the day At ten o'clock A. M. I was ordered to take position in the rear of the battery as reserve. This I did with the whole of my command, with the exception of Captain Well's company, which was not in the engagement, and Captains Bostic and Robinson, who since report that they became detached and were engaged to the right of General Parson's battery At eleven A. M. my command took position according to order at right and left of our battery and commenced approaching the enemy under cover of bales of hemp, rolling them before us, which formed most effective protection and saved many valuable lives Under this protection we moved forward until within fifty paces of the enemy's fortification with but little loss. After gaining our position, and an incessant firing for several hours, the white flag was displayed upon the enemy's embankments opposite my command. Our men sustained a constant fire from both artillery and small arms, but they stood their ground like veterans and answered not only shot for shot but two for one with most destructive aim. Too much praise cannot be bestowed upon our noble recruits. The officers above named, who were under my personal observation, together with Maj. J. J. Hash and Lieut. E. W. Toole, acting adjutant of my command, fought like free Missourians who knew their rights and dared defend them. The following is the list of killed and wounded in my command: Killed: F. M. Breman. private, Kelly's artillery; Jeff Warren and Win. Wren, privates, Minter's company. Wounded: Lieut. H. H Moss, in arm, Privates Fays, W. A. Chesnah, slightly, Minter's company, Buchanan county; G. H. H. Brand, in neck, G. R. Smith, in arm, A. J. Rucker, in arm, W. Thomas, in hand, Gibson's company; A. L. Wilson, in arm, John Kelly, in thigh, J. Absom, in hand, Kelly's artillery; J. Lynch, in hand, W. Smith, in knee, J. R. Hooper, slightly. Smith's company. Total killed, 3; wounded, 13; killed and wounded, 16.
Yours obediently,
JOHN R. BOYD, Lieut. Col. Commanding.
The battle of Lexington, fought in and around the city of Lexington, Missouri, on September 18th, 19th and 20th, 1861,
by forces under command of Colonel James A. Mulligan, and General Sterling Price. The official records of both parties to
the conflict; to which is added memoirs of participants.
Lexington Historical Society, Lexington, Mo. (1903) pp. 61-62