In the fall of 2008 an image of a letter was posted at an auction gallery website. By December 28, 2008 the letter had been sold. What follows is a transcript of that letter from Thomas C. Fisher, in Company C of the 125th Pennsylvania to his father.
I've added annotations to the letter. These annotations come mainly from the History of the One Hundred and Twenty-fifth Regiment Pennsylvania Volunteers, 1862-1863 by the Regimental Committee (Philadelphia: J.B. Lippincott, 1906), particularly the memoir of Capt. William W. Wallace published in that history.
Maryland Heights Oct 5th
I had a letter from you some two or three days ago and one from Rash written from New York, and of course they were welcome as news from home is the greatest enjoyment of the soldier. I wrote to you from the Heights yesterday was a week ago, the day after we were moved around on the hill above Sandy Hook[. ]
[W]hile encamped there we were visited by Mr. Strickler, Hagy and Squire Snow and John Fockler whom we were all of course glad to see the Old Squire[,] luckily for him[,] had a pleasant night to stay in camp[,] if he’d been with us last night I am afraid he would have suffered a little. On Friday we were moved back again to our present encampment, last night up where we are now. It was unpleasant both to sleep without tents or any shelter of any kind.
You asked in your letter who took charge of the Colors after Geo. Simpson was shot. [F]or my part I did not see anything of them myself as my position was at the right end of the company, when the firing commenced. I stopped some four paces in the advance of the company line as I was more afraid of being shot by the rear rank than by the rebels. I got down on my knees and loaded and fired as fast as I could deliberately, as there is no use wasting ammunition shooting into trees. The order to retreat was given to our company three times before it was obeyed.] [U]ntil I turned around to retreat I did not know there was a single man hurt. The first man I saw was Nicholas Decker badly wounded about the ankle, his ankle bone shattered badly. Capt Wallace, Lieut Ziegler and I helped him behind a large tree when we were compelled to leave him (we have since heard from him he is in one of the Hospitals, his leg was amputated below the knee). After I came out into the field about twenty paces, a member of the 102 New York scrambled up off the ground and prayed me to help him. Of course I could not refuse if my life paid the forfeit. I assisted him the whole way over the field to a place of safety under fire, and perhaps it was my act of mercy to him that saved me. The only running I did was across the field to get out of the range of our battery which was beginning to open on the enemy before I had gotten away from the font of it.
But to return to the colors[.] [T]he true version of the affair as nearly as can be ascertained is as follows. George Simpson was shot dead in the ranks in the woods, the colors were then picked up by a boy in Capt. Gregg’s[5a] company by the name of Eugene Boblits he carried them some thirty paces when he received a ball in his leg and fell. A young fellow in our company by the name of Peterson then called to Walter Greenland “there is the Colors, ” bring them off! Walter picked them up carried them some thirty or forty paces and handed them to Capt Wallace who brought them off the field.
I suppose Rash will be home in a few days with new goods, when you will of course be busy for a while at least. I wish I was there to help you, as you having been sick may overexert yourself.
My love to Mother sisters and all friends. Your affectionate Son Tom
 William W. Wallace, Captain, Company C of the 125th Pennsylvania contributed to the regimental history an essay titled “Reminiscent and Historical.” In it, he recounted the regiments action at Antietam. “We arrived at Harper’s Ferry about noon on the 19th, and were kept shifting to and fro between Maryland Heights and Pleasant Valley until October 3d, during which time much sickness prevailed and many died from camp fever, etc.” History of the One Hundred and Twenty-fifth Regiment Pennsylvania Volunteers, 1862-1863 by the Regimental Committee (Philadelphia: J.B. Lippincott, 1906), pp. 179-80 (hereafter, History).
 Color Sergeant George A. Simpson was killed in the West Woods that day. The statue to the 125th Pennsylvania is modeled after him.
 William L. Zeigler, 1st Lt. Company C.
 Wallace writes: “Early on the morning of the 18th I accompanied a detail in search of my own compay’s killed and wounded. …Nicholas Decker was our next ‘find.’ Stretched upon the ground with a badly shattered leg, he had been lying there helpless and exposed all these weary hours. All that hospital care and skill could do was done for hime, but he lingered and died October 11th.” History, p. 175.
 “The events following the collapse of the southern end of the West Woods unfolded very quickly. To most of the men, the one hundred yard dash from the church to the cover of Monroe’s Battery seemed much longer. The survivors of the 125th Pennsylvania found themselves trapped between Battery D, 1st Rhode Island Battery [Monroe’s Battery] and Kershaw’s South Carolinians.” John M. Priest, Antietam The Soldiers’ Battle, (New York: Oxford University Press, 1989), p. 122.
[5a] Captain Henry H. Gregg, Company H.
 Eugene J. Boblits of Company H. “Born December 21, 1846, he was probably one of the youngest soldiers in the army [15 years old at the time of Antietam]. He was one of the color-guard at Antieta, and when that gallant color-bearer, Sergeant George A. Simpson, was killed, Boblits bore the colors until he was also prostrated by a bullet, which left him crippled for life.” History, 207
 William H. Peterson, Company C.
 Sgt. Walter Greenland was in Company C. He survived the war and became, on March 8th, 1892, Adjutant-General of Pennsylvania. History, 208
 Wallace recounted: “The next object that immediately claimed my attention was Seargeant Walter W. Greenland approaching me with the flag in his possession, which he had just received from one of the color guard, who had been wounded. As Walter was not one of the color guard, I relieved him of it, to use it in rallying the regiment.” History, 173.