FORT LYON, COLO, TER., June 27, 1864.
Lieut. H. L. ROCKWELL,
    Actg. Asst. Adjt. General, Military Dist. of Colorado:
    LIEUTENANT: I have the honor to transmit, for the information of the colonel commanding, the following report of all the information I could gain by means of scouts, thrown over toward the border of Texas, in the neighborhood of the Cimarron and Red Rivers, in regard to the movements of an enemy in the direction of Texas:
    The first scouting party that left this post for that purpose under my orders started on the 16th of May, 1864, was gone eight days and returned, bringing no information whatever.
    The next, 6th of June, reached a point north of Cimarron crossing, finding a train of wagons that had been attacked by a party of men, numbering about 30, from which they had taken 70 head of mules and $10,000 in money, taking with the mules the harness, the singletrees, and fifth chains, all this occurring about the 26th day of May, 1864. The marauding party had evidently departed from the scene of their depredation in a southwesterly direction. Since the above-mentioned depredations, various rumors being circulated of the approach of a large body of Texans, I have kept scouting parties constantly out; the last report being on the 26th of June, 1864, from Lieutenant Oster, First Cavalry of Colorado, commanding detachment of 15 men on scout.
    He left this post June 7, 1864, proceeded to Bent's old fort, 35 miles west of Fort Lyon, crossed the Arkansas River, and traveled southeast 116 miles; crossed the Cimarron, and from thence proceeded 65 miles due south. He was then forced to return 25 miles and traveled nearly due west 60 miles; struck a trail leading due west, which crossed Rabbit Ear Creek 50 miles south of the Santa F� road. Here he found evidences of some horses and mules having passed toward the west within a space of ten days. Having but three days' rations remaining he was obliged to return, traveling northeast 70 miles; crossing the Cimarron 15 miles west of the Santa F�, traveled due north 93 miles to this post. The distance traveled, 464 miles; time, 17 days; miles traveled per day, 27 5/17.
    All of which is respectfully submitted.
        I am, with respect, your obedient servant,
                                                         E. W. WYNKOOP,
                      Major First Cavalry of Colorado, Commanding Post.

Source:

United States. War Dept., United States. Record and Pension Office., United States. War Records Office., et al., "Red River Campaign," The War of the Rebellion: A Compilation of the Official Records of the Union and Confederate Armies. Prepared by The late Lieutenant Colonel Robert N. Scott, Third U. S. Artillery, Published Under the Direction of The Honorable Redfield Proctor, Secretary of War, By Major George B. Davis, U. S. A., Mr. Leslie J. Perry, Mr. Joseph W. Kirkley, Board of Publication. Series I-Volume XXXIV-In Four Parts. Part IV-Correspondence, Etc. Washington: Government Printing Office. 1891. p. 576.