Jonathan Dormayer and his brother David Dunmeyer served with Sheridan in the Shenandoah Valley in the fall of 1864. They were in separate regiments. David was severely wounded on September 19, 1864 and Jonathan was severely wounded on October 19, 1864--the day of Sheridan's famous ride to rally the troops. The following excerpt from Volume III of the 1877 book "Pictorial History of the Civil War in the United States of America" tells the story of that fateful one month period.
The following image is Thomas Buchanan Read's 1871 painting of Sheridan's famous October 19, 1864 ride:
The following image is Thure de Thulstrup's circa 1881 painting of Sheridan's famous October 19, 1864 ride: