Today’s post is written by Dr. Greg Bradsher, Senior Archivist at the National Archives at College Park
Captain Marcy, from Camp on Fontaine qui Bouille, on April 6, wrote a family member, that for the past several days they had been traveling towards Utah, without anything of interest occurring to please or annoy them:
The weather has been beautiful, and our animals which constitute the principal objects that require my attention, are doing well. We have to remain about ten days at this place, awaiting Colonel Loring’s arrival, with large reinforcement to join my command, and proceed with us to Camp Scott.
We have great abundance of game here, and indeed, we have not been without deer, antelope, turkey, or bear meat for the last three weeks. This with onions, potatoes, etc. makes our fare better than it was on our trip over the Mountains last Winter.
It will probably be two months yet before we get back to the Army, and we are very impatient to get there. By the time that we get back, the troops from Leavenworth will probably be near the army. We shall have about 450 men in our party, and if the Mormons come out to meet us it will be for the purpose of trying to stampede and run off our animals in the night, but they will not attempt to fight us. We shall keep out scouts all the time, and if they come near us, we will know it before they have an opportunity to get any of our animals.
The reference Marcy made to the troops from Leavenworth were the reinforcements being sent to join Colonel Albert Sidney Johnston’s army. The first contingent, consisting of the rest of the 6th Regiment of Infantry departed Fort Leavenworth on May 7. Three more columns followed during May and June, under the command of Brigadier General William S. Harney.
Meanwhile, Colonel Loring’s command, some 200 soldiers, left Fort Union on April 7 and 8. The command consisted of Loring, 2nd Lt. McNally and 2nd Lt. Tilford of the Regiment of Mounted Riflemen, three bandsmen; members of Company K (the remainder were already with Marcy under Lt. Du Bois) and detachments from H and G of the Regiment of Mounted Riflemen under the command of 1st Lt. Alexander McRae (of Company K); Companies F and E, 3rd Infantry, respectively under the command of Capt. John Trevitt and Lt. A. N. Shipley, of the 3rd Infantry (the two companies having a few days before reached Fort Union from Albuquerque, 160 miles).
In the meantime, Marcy’s party remained in camp for three weeks. They amused themselves in hunting elk, mountain sheep, and black-tailed deer; all of which were very abundant in the surrounding country. This supplemented their normal rations. Marcy often went bear and buffalo hunting.
On April 27, when Loring’s party was some 12 miles distant from Marcy, Loring sent an order to him assuming command and requesting him to join up as early as practicable. The next day Loring and his reinforcements met up with Marcy’s command, and together on April 29 the combined force of ten officers and 329 enlisted men marched to an elevated ridge which divided the waters of the Arkansas from those of the South Fork of the Platte River. By late afternoon, Loring’s part of the command, unencumbered by having to escort the animals, had moved some six miles ahead of Marcy’s part of the command.
According to Marcy, the day was bright, cheerful, and pleasant, the atmosphere soft, balmy, and delightful, the fresh grass was about six inches high, the trees had put forth their new leaves, and “all nature conspired in giving evidence that the somber garb of winter had been cast aside for the more verdant and smiling attire of spring.” The large herds of animals were turned out to graze upon the tender and nutritious grass that everywhere abounded. The men, he wrote, were enjoying themselves and the fatigues of the day’s march, and everything “indicated contentment and happiness.” Du Bois decided to ride over to Loring’s camp after dinner to see members of his Company K.
As night approached, it became cloudy and windy, and about dark it turned cold and, as Marcy would later write, it “soon commenced snowing violently, and continued to increase until it became a frightful winter tempest, filling the atmosphere with a dense cloud of driving snow, against which it was utterly impossible to ride or walk.” Marcy immediately set the soldiers to work making corrals for the animals, but before all were secured one herd of 300 mules and horses stampeded and broke away in spite of the utmost efforts of the herdsmen, and ran at full speed, directly with the wind for fifty miles towards the Arkansas River before they stopped. Marcy, in his official report, wrote that:
Of three Mexican herdsmen who followed them, one perished from the cold, actually freezing to death, and another was found crawling over the prairie after the storm ceased, in a state of temporary insanity with his limbs badly frozen. He was brought to camp and subsequently recovered. Another man perished within 200 yards of the camp, and the charred remains of a fourth were found where a fire had been built, with the flesh entirely burned off. It was supposed that the latter had lain down by the fire when so chilled and benumbed as to be quite helpless and that while in this condition he accidently fell into the flames, from which he could not extricate himself. The deceased were all New Mexicans. After the storm subsided the stampeded animals were found scattered over the country on the Arkansas but nearly all of them were recovered.
I had fortunately preserved a quantity of corn, which was fed out to the animals during the continuance of the storm, and this probably prevented any of them from perishing with cold or hunger. Nearly all the animals were recovered after the storm had ceased.
Marcy wrote that the instincts of all their animals, excepting the one herd mentioned, led them to seek shelter in a grove of timber near camp, where they were somewhat protected from the fury of the gale. He added they had with them a flock of sheep, which scattered throughout the timber in every direction during the storm, and afterward were nearly as wild as deer; they, like the insane herdsman, seem to have lost their senses.
Du Bois, who had rode six miles to Loring’s camp after dinner, started to return when the storm suddenly arose and he could not find the way, it was so very blinding. Returning, he sat down by Lieutenant McNally’s fire but this soon became worse than nothing. They went to bed early. The morning of April 30 came and still the storm raged with redoubled fury. He wrote: “Our beds were covered with snow to the depth of two feet. It was almost impossible to stand before the fury of the wind. A fire could not be lighted and cold, raw bacon was all we could find to eat. Half the tents were down and the men under them covered with drifts of snow.” Du Bois wrote that Loring was sick and the doctor was sleeping on the ground by Loring’s cot. He added:
During the night of April 30 the tent came down. As the snow drifted on it, its weight became unsupportable to those under it and after attempting unsuccessfully to obtain relief the Doctor was forced to upset Loring’s cot and by rolling him off this cot supported the tent high enough for breath. Not a soldier was visible. All our stock had stampeded. Nothing was left in camp but McRae’s horses. All day it snowed. At night I slept in McRae’s tent. We could not sleep it was so cold. We drank four quarts of liquor during the day when we were in the snow without feeling any effect. During the night we heard cries and opening our tent two Mexicans stumbled in almost dead. Their limbs and faces were completely frozen. One had carried the other for half a mile and being lost in the drifting snow, our light had saved their lives. We rubbed their limbs and gave them blankets and in two hours they were almost comfortable. In the morning a dead man was found within one hundred yards of our tent, frozen to death.
According to Du Bois it still snowed on, but by night May 1 there seemed to be some prospect of change. He wrote:
The men were turned out from their nests under the snow and some attempts made to cook. The evening brought an express from Marcy. All his herd had stampeded. This morning, May 2, it had ceased snowing. We buried the man who was frozen to death and afterwards I returned to my own camp. The snow on the road was in places four feet deep. I was four hours going six miles, and on arriving my horse fell down and has not been able to stand since. The marks of the storm are everywhere around us. Dead sheep, oxen and horses are scattered in every direction. Even antelope mixing with the sheep froze to death with them. The herders are in every direction looking for the mules and some were brought in this evening. One of the herders froze to death and his body was this moment brought in. The snow has drifted around Marcy’s corral to the depth of twenty feet. These three days have been terrible. I had but little hopes of saving all the men and at one time feared that all would freeze.
In his official report Loring wrote the storm had begun on April 29 and continued unremittingly until May 2:
When its violence somewhat abated; the cold and violence of the wind was so great that human life was in constant peril; a civilian teamster in the quartermaster’s employ was frozen to death, and several hundred sheep perished in the storm; a large number of horses and cattle belonging to citizens travelling with the command also perished; a number of mules broke through control and fled before the storm, many as far as sixty miles; the entire number with but few exceptions were recovered. Marcy, whose herds were seven miles back, used every exertion to save them; in the fury of the storm some 300 of his mules fled in the same manner as in our camp; they also with few exceptions were finally recovered, and I believe only those in both instances which perished in the storm were lost; in both camps a large number were badly frostbitten and otherwise injured; the snow on a level was two and a half to three feet deep, and when drifted fifteen to twenty feet; the antelope of the prairie were frozen to death, numbers of them in our immediate vicinity, mixing among our sheep for protection and perishing with them.
At the termination of the tempest there was about three feet of snow upon the ground, but the warm rays of the sun soon melted it and on May 3 the orders were given to resume the march. Before heading out once again, the soldiers counted their animal losses (at both Loring’s and Marcy’s camps) at 350 sheep, ten horses, 300 mules, and 75 cattle, as well as animals belonging to civilians traveling with the army.
On May 5 the party again resumed the march down Cherry Creek aiming for its confluence with the South Platte. It was very cold and the mud was a foot deep. Traveling was hard on man and beast. They camped on Cherry Creek. All the while it continued to snow. They got a late start in a cold rainstorm on May 6, with mud up to the horses’ knees. About 10am the rain changed to snow. Again they encamped on Cherry Creek, with snow nearby nearly 10 inches deep. During the day 39 more mules were brought in by one of the herders, having gone after them after the major snow storm of days previously.
The party awoke on May 7 to snow twelve inches deep and the mud beneath still deeper. Loring issued the order to march that day. Du Bois would be in front of the column by more than a mile with guides and scouts. The advance and rear guards were of infantry. The herd, guarded by the Mounted Riflemen would follow the advance guard. They in turn would be followed by the train of wagons. The party traveled 10 miles, continuing to find good grass, water, and wood throughout the valley of Cherry Creek. It snowed all day but seemed to melt faster than it fell.
In spite of snow and mud in the morning of May 8 Loring decided to make a march that day. They followed down Cherry Creek. It snowed and rained slightly every hour and it was very cold. Mud and snow impeded their way. However, with every foot brought them to what seemed to be a warmer climate. By midday, having marched seven miles, heading northwest, they reached a warm camp on Cherry Creek where the old grass was above the snow, and stopped. On May 9, heading northwest, they marched all day, as it snowed and rained, making only 12 miles. It was another struggle, the mud up to the axles of the wagons. They camped on Cherry Creek, finding wood, water, and grass.
In the meantime, Brevet Lt. Col. William Hoffman’s supply train, with two companies of infantry, left Fort Laramie on April 24 and encamped sixty miles west on the Oregon Trail at LaBonte Creek on April 29. That same day two more companies of the 6th Regiment of Infantry joined up with Hoffman’s command. Hoffman was eager to move as fast as he could to get supplies to Johnston. However, his party was hit by the same snow storm on April 29 as had paralyzed Loring and Marcy. It was not until May 11 that Hoffman was able to get his command moving again.
As Loring and Marcy and their men advanced on May 10 the roads improved and by the time they reached the South Fork of the Platte where camp was made, having traveled northwest over 17 miles. Although they found the valley at the confluence of Cherry Creek and the South Fork of the Platte a beautiful place, with abundant grass, wood, and water, the river was rapid and at a high stage, 12 feet deep. Thus, they had to build a flatboat and ferry everything over.
While the flatboat was being constructed, one of their citizen employees washed from the sands of Cherry Creek a small amount of gold-dust, which he showed to Marcy. Soon afterward he was discharged and went to St. Louis, and in a short time the miners commenced flocking to the locality, and laid out a town, called Denver City.
For most of the night of May 10-11 the soldiers were busy getting out timbers for the ferry-boat. At daylight on May 11 the work began again and lasted all day. That evening fires were burning all around the workmen as they constructed the flatboat. By noon of May 12, when they were able to stretch a rope across the river, they swam the horses over without a loss. The mules were not quite as fortunate. Five were drowned. At 3pm the flatboat was finished and at 9pm all the infantry had crossed. They were forced to stop on account of the darkness.
They got an early start on May 13 and by 8am all the Mounted Riflemen were on the right bank of the river. During the day some 47 wagons were transported across the river in the flatboat. It was hard work Du Bois recorded, as well as of the fact that he was wet to the skin, cold, and exhausted. On the morning of May 14 the remaining 28 wagons were crossed over the River. With everyone across the march resumed that day. As they anticipated finding the North Platte River, some 200 miles in advance, above fording stage, they determined to haul their flatboat to that point. Accordingly, they mounted it upon a stout wagon drawn by a team of twenty mules, and transported it the entire distance.
They continued upon the Cherokee trail skirting the eastern base of the Rocky Mountains, and crossing small tributaries of the South Platte, until they reached the Cache la Poudre Creek, some 70 miles distant. For a distance of 200 miles up to this point, from the base of the Raton Mountains, the road had taken them northward, skirting the eastern base of the Rocky Mountains. The path would soon change.
At Cache le Poudre on May 17 Du Bois wrote his mother about the snow storm. He wrote that they were caught in the mountains by the most terrible storm he ever saw and that men who had passed 30 or 40 years in the mountains said they had never seen such a storm. The snow, he noted, was eight feet deep in places. He pointed out that he was away from his camp [visiting Loring’s camp] and could not return for three days. He wrote that when he awoke after the first night, his bed was two feet deep in snow. He added that their animals stampeded and were only recaptured sixty miles distance after many had been frozen to death: “the entire plain after the storm was covered with frozen sheep, mules, horses & cattle.”More than 200 sheep were frozen to death. Additionally, they had two men frozen to death, one within 200 yards of camp. Also, one poor fellow was missing besides the two frozen to death and they subsequently learned that the bones of a man were found in the timbers who had built a fire and while lying by it had been completely burned up. Probably he was so frozen that he could not move. Since this storm, he continued, they had struggled on, with their animals exhausted and the roads almost impassable from snow and mud. He wrote that after ferrying over the South Fork of the Platte all the streams had been very deep and rapid, and that they were delayed every day by storms of rain, hail, and snow. “Every night finds us wet & exhausted, but we struggle on yet & have hopes of a better time coming.” He ended by expressing his wish that some members of Congress were with them. If they were, they would never talk of “‘our kid glove army officers’” again. He informed his mother that the letter would reach her by Fort Laramie (some 150 miles to the northeast).
After leaving the Cache le Poudre, the command left the plains and bore left, turning into the mountains, and making a very gradual ascent into the mountains. They passed over a high rolling country, crossed the main fork of the Laramie River on May 21, and on May 23 they bore around the northern base of the Medicine Bow Butte [Elk Mountain] and camped on Medicine Bow Creek. On May 24 the party remained in camp and started out again the next day.
By midday on May 26 they reached the North Fork of the Platte River. The current was very rapid and the river about sixty yards wide. However, they did not use the flatboat they had brought when, as it was thought the river was fordable. They crossed the horses without difficulty, but the wagons reached the opposite bank with animals so exhausted that four mules were drowned only a few feet from shore. On May 27 everyone remained in camp recovering their wearied animals and preparing for a severe march over the only barren country they expected to meet on the road.
When the march resumed on May 28, they left behind the flatboat for any future travelers who needed it, and headed northwest, continuing northwest over a rolling country without grass. They met with a piercing wind, rain, and snow, and halted every hour to build a fire of sage brushes, which was everywhere along the road, and constituted the only fuel between the Platte and Green River. After only making 12 miles in six hours they reached a camping area on Sage Creek. There an express rider was sent to Camp Scott/Fort Bridger. The message from Loring was that the strength of his command was 346 soldiers and 162 civilian employees and had rations enough for all for another 20 days. He also reported that the animals were all in good condition.
From Sage Creek they set out westward over an undulating and elevated plateau for 65 miles throughout which they found occasional ponds of water, but saw no running streams, and little grass, but lots of sagebrush. This section of arid and barren country terminated at the head of a small tributary of Bitter Creek, which they descended to its mouth, following its north bank to its confluence with Green River, and from thence intersecting the Fort Laramie- South Pass Road (the Oregon Trail).
Meanwhile, Johnston, who had been promoted to Brevet Brigadier General earlier in the year, was eager to begin the movement of his forces against the Mormons. His major preoccupation was with assuring supplies of rations, clothing, and animals. He counted on Hoffman and Marcy meeting those needs. He intended to move ahead as soon as the supplies with their escorts arrived and not to wait for the massive reinforcement. The new governor, Alfred Cumming who had come west with Johnston, was eager for a peaceful settlement and had gone to Salt Lake City in April and met with Brigham Young and church leaders for three days. Already, Brigham Young had ordered upwards of 30,000 residents of Salt Lake City and the northern Utah settlements to move southward to Provo and beyond. Some people believed he was taking the Mormons to Sonora, Mexico. Others believed that Young intended to move into the mountains and mount guerilla warfare. He had already sent out explorers to the White Mountains (at the Utah-Nevada border) to ascertain whether it would be suitable to accommodate the Mormons.
Young and his associates assured Cumming he would be accepted as the Governor, but desired that the Army not be stationed close to their settlements. President Buchanan also desired a peaceful resolution. In early April he appointed Lazarus W. Powell, formerly governor of Kentucky and senator-elect from the state, and Ben McCulloch, who had served in the Texas revolution of the 1830s and during the Mexican War, and was then U.S. Marshal for the Eastern District of Texas, as commissioners, to take a proclamation and pardon to Utah. The Presidential Proclamation, issued on April 6, threatened punishment as traitors for those who persisted in their resistance, but offered a “free and full pardon” for all who would submit themselves to the federal authority. The military forces, Buchanan said, would not be withdrawn “until the inhabitants of that Territory shall manifest a proper sense of duty which they owe to this Government.”
Powell and McCulloch reached camp Scott on May 29. After conferring with Cumming and Johnston they wrote the Secretary of War on June 1, that the “leaders of the Mormon people have not given the governor correct information as to the condition of affairs in the valley,” that the Mormons were still in arms guarding the approaches to Salt Lake City. They thought the presence of the Army the best guarantee that the Mormons might submit and deemed “it a matter of first importance that the army advance into the valley of Salt Lake before the Mormons can burn the grass or harvest or burn the growing crops.” They did, however, want to confer with the Mormon leaders before the Army marched. They arrived at Salt Lake City on June 7 and were joined shortly afterwards by Governor Cumming. They then waited for Brigham Young and Mormon leaders to come up from Provo to meet with them.
On June 6 Marcy, Loring, and their men traveled 17 miles to the Green River where they found wood and grass abundant. There they met the express rider who had been sent out on May 28. He brought letters, a newspaper dated April 30, and an order signed by Johnston in which he complimented Marcy for the management of his expedition to New Mexico. The soldiers went into camp and while their meals were cooking read over all the news. At 3pm they broke up camp and found a good fording place across the Green River and made camp.
The command marched some 20 miles on June 7 and camped on Black’s Fork. This route took them over the trail of the Army of Utah the previous November. Dead animals half preserved by the snow lined the road. At this point they figured that not more than 24 hours in advance was Hoffman’s command escorting supplies. Marcy recorded that day he had travelled 612.73 miles since March 23. Loring, Marcy and their force and animals headed west on June 8, traveling 16 miles that day. They followed Black’s Fork for some distance, crossing it twice, then leaving it, crossed Ham’s Fork where they found a bridge guarded by an infantry officer and twenty men. Here they rested half an hour, and after hearing all about the Mormons, they went on to Black’s Fork again and encamped.
In the meantime Johnston had ordered Hoffman to send forward in advance of his command a train lightly laden with fifteen days’ provisions, and to expedite matters, Johnston on May 21 sent an officer, thirty men of the 2nd Dragoons, and 75 mules to replace those animals of Hoffman’s command that had broken down. Hoffman with his advance train arrived at Camp Scott on June 8. The remainder of his command, with the bulk of the supplies, arrived two days later.
After an early start on June 9 the Loring-Marcy command traveled 15 miles and camped early at Muddy Creek. Loring, Marcy, Du Bois and an escort of ten men, in a slight snowstorm, then rode 20 miles to Camp Scott. Johnston had asked Loring and Marcy to come in advance of their command and was undoubtedly pleased that the needed horses and mules would soon arrive. Loring and Du Bois the next day rode back to the command, which traveled 16 miles and camped on Black’s Fork, three miles from Camp Scott. On June 11 they brought the command into Camp Scott and they joined the Army of Utah, having traveled some 765 miles from Fort Union.
At Camp Scott on June 11 Loring wrote the Assistant Adjutant General, Headquarters of the Army that “from the time I first communicated with Captain Marcy, I received his cordial and able assistance upon all occasions; the direction of his large herds was given with his well known energy, and, in the end, secured a successful termination of his expedition to New Mexico.” The next day Loring wrote the Adjutant General of the Army that the command from New Mexico reached Camp Scott on June 11 “all well and in good condition.” The animals in charge of Marcy, and which were purchased in New Mexico, for the Army of Utah, were all in fine condition.
On June 11 and 12 Powell and McCulloch met with Young and Mormon leaders. They accepted the presidential pardon, all the while protesting they had done nothing to require it except for the raids on the army supply trains. Powell and McCulloch would later report to the Secretary of War that “Upon the President’s views and intentions being made known…it was agreed that the officers, civil and military of the United States should peaceably and without resistance enter the Territory of Utah, and discharge, unmolested, all their official duties.” They added that the army would establish in the territory the military posts necessary to prevent Indian depredations, protect emigrants, and “to act as posse comitatus to enforce the execution of civil process should it be necessary.” If the inhabitants submitted to the execution of federal laws and peaceably received the federal officers, there would be no need for such posses. If they refused or otherwise resisted the execution of the federal laws, “the President would employ if necessary the entire military power of the nation to enforce unconditional submission and obedience to the Constitution and laws of the United States.”
On June 12 Johnston made Marcy Acting Inspector-General of the Department of Utah and the next day Johnston started his forces toward Salt Lake City. On June 14 they reached Bear River where they received a communication from Powell and McCulloch. In keeping with their suggestion Johnston immediately issued a proclamation to the people of Utah that they had nothing to fear from the army and that it would protect their persons and property as long as they obeyed federal laws.
Johnston would lead his army through a deserted Salt Lake City on June 26 and continued it southward, where he established the headquarters of Department of Utah at Camp Floyd, 45 miles south of Salt Lake City and 30 miles west of Provo.
It was here that Marcy received a letter from General Scott’s Aid-de-Camp, dated May 29, in response to his March 29 letter. Lt. Col. George W. Lay wrote Marcy that:
Sir, I am instructed by Scott to say to you in reply to your letter of March 29, that the “unconquerable energy, patience, and devotedness to duty displayed by yourself and the command intrusted to your skillful guidance and direction, have been highly appreciated by himself, and that the unusual sufferings and hard labor to which the troops were exposed in accomplishing their arduous march in the depth of winter has been made known to the whole country by the public press. It is impossible, under such circumstances, that your name should be dissociated from the efficient aid rendered to the army of Utah by the return of the expedition which you so successfully conducted. But the General-in-Chief, upon information communicated by General Johnston, of a probable attempt on the part of the Mormons to cut off the expedition, deemed it proper to instruct General Garland to reinforce your escort, and the extent of that reinforcement perhaps necessarily involved the addition of an officer senior in rank to yourself, to take charge of the troops thus detached from the department of New Mexico after their connexion with your expedition shall cease.
The General-in-Chief will not fail to commend your admirable conduct to the special notice of the War Department.
Enclosed was a letter from Scott to the Secretary of War, in which the General-in-Chief expressed his opinion that Marcy “has again richly earned by gallantry and good conduct, the rank of major by brevet.”
In his annual report to the President, the Secretary of War on December 6, 1858, wrote that “the conduct of both officers and men attached to the army of Utah has been worthy of all praise.” As for Marcy he observed that: “it is but just to bring the conduct of this officer and his command to your especial notice. It may be safely affirmed that, in the whole catalogue of hazardous expeditions scattered so thickly through the history of our border warfare, filled as many of them are with appalling tales of privation, hardship, and suffering, not one surpasses this [his trip to New Mexico]; and in some particulars it has been hardly equaled by any.”
Secretary Floyd then provided a brief account of the trip to New Mexico and noted Marcy’s return trip had been delayed by having to wait for reinforcements. Floyd also transmitted “a short report prepared by Captain Marcy, at my request, which, I am sure, will be read with interest.”
President Buchanan, in his annual message to Congress, on December 6, wrote that Powell and McCulloch had reported on July 3 that they “‘are firmly impressed with the belief that the presence of the Army here and the large additional force that had been ordered to this Territory were the chief inducements that caused the Mormons to abandon the idea of resisting the authority of the United States. A less decisive policy would probably have resulted in a long, bloody, and expensive war.’” He added that “I am happy to inform you that the governor and other civil officers of Utah are now performing their appropriate functions without resistance. The authority of the Constitution and the laws has been fully restored and peace prevails throughout the Territory.”
During the summer of 1858 Marcy was recalled to the east coast to write, at the request of the Department of State, a handbook for western travelers. This turned out to be the popular The Prairie Traveler: A Handbook for Overland Expeditions, with Maps, Illustrations, and Itineraries of the Principal Routes between the Mississippi and the Pacific (1859). He was promoted to Major in August 1859 and promoted to Brigadier General, U. S. Volunteers, on September 23, 1861. He saw action in the Western Virginia campaign during the summer of 1861 and served with the Army of the Potomac during its 1862 Virginia Peninsular and Maryland Campaigns, acting as Chief of Staff to his son-in-law George B. McClellan.
Marcy would be made Brevet Major General in the U.S. Army in March 1865. After the Civil War he would author Thirty years of army life on the border (1866). Marcy would retire from the Army in 1881 and pass away in 1887.
The itineraries of the travels of Marcy and Loring, as well as their reports, are printed in Message from the President of the United States to the Two Houses of Congress at the Commencement of the Second Session of The Thirty-Fifth Congress, December 6, 1858, House of Representatives, 35th Congress, 2nd Session, Ex. Doc. No. 2, Vol. II, Part II. This volume also contains many of the documents referenced above. Other U.S. Army documents can be found in Letters Received by the Office of the Adjutant General, 1822-1861, (NAID 300368) Record Group 94: Records of the Adjutant General’s Office, 1780s-1917.
Also useful are the two works published by Marcy and Campaigns in the West 1856-1861: The Journal and Letters of Colonel John Van Deusen Du Bois with Pencil Sketches by Joseph Heger, ed. by George P. Hammond (Tucson: Arizona Pioneers West Society, 1949).