Thanks for the info. Having his first name, I was able to find a little more info on the internet:

http://www.kancoll.org/books/cutler/miami/miami-co-p2.html

KANSAS COLLECTION BOOKS
William G. Cutler's History of the State of Kansas

Pat Devlin, the originator of the term "jayhawking" was killed in the fall of 1860, in Aurora, Col. And it is a remarkable coincidence that "Marshall Cleveland," the last and by no means the least of the "jayhawkers" should have been killed on almost the exact spot where the name originated. Marshall Cleveland was known at different times by different aliases. His real name was Metz, and he came to Kansas from Ohio. He was a man of commanding stature, tall and muscular, and brave to a fault. He first made his appearance on the border in 1861, as one of Jennison's jayhawkers. On the 14th of October, he was mustered in as Captain of Company H, Seventh Cavalry, but unable to bear the restraints of army life, he resigned his commission November 1st. Gathering about him a number of men of his own class, he commenced a course of robbery and plunder in the name of "Liberty." Having stolen $125 from H. L. Lyons and considerable property from Joseph and John Beets, himself and two of his confederates, named respectively "Buckskin" and "Rabbit Ear" were indicted for robbery at the March term of the district court. A State warrant was issued for Cleveland, and the sheriff made several ineffectual attempts to arrest him. He laughed at the civil authorities and defied the military. He was declared an outlaw and Capt. H. S. Greeno, Company C, Sixth Kansas Cavalry, in command at Paola, sent out two soldiers in citizens' clothing, to ascertain his whereabouts. On the 10th of May they found him at the Geer Hotel in Osawatomie. On the same day the Sheriff attempted to arrest him, but failed to procure a posse equal to the task. Capt. Greeno proceeded to Osawatomie in the night. Approaching the town he picketed the roads with a portion of his forces under Sergeant Morris. As daylight approached Sergeant Mooris drew in his men, surrounded the Geer Hotel, and before Capt. Greeno reached the hotel, had received Cleveland's surrender. Cleveland being allowed to dress and come out of the house, sprang upon his horse, which some friend had brought him, broke through the guards and dashed off in the direction of the Pottawatomie, followed by the whole command. Capt Greeno and Private John Johnson, being finely mounted, rapidly gained upon the outlaw, and when within range were fired upon by him several times. On arriving at the bank of the creek he dismounted and ran down the steep bank. Johnson also dismounted and approaching the bank, fired a fatal shot at Cleveland from above. He was buried in the Osawatomie cemetery and some time afterwards his "wife" caused to be erected at the head of his grave a monument bearing the following inscription:

MARSHALL L. CLEVELAND
May 11, 1862
Earth counts a mortal less
Heaven an angel more

This is not so much "a new departure in gravestone literature," as it is considered by an excellent local historian as it is an apotheosis inspired by a woman' love.