Vol 2 of "Confederate Cemeteries" by Mark Hughes says:

"The first Confederate soldier buried in Thornrose Cemetery was D.C.McLeweray, 3rd Ark. On 7/9/1861 he was struck & killed by a train while debarking at the C&O Depot."

Staunton's location made it a secure location for hospitals. Many sick & wounded soldiers were taken there. Those who died were buried in Thornrose Cemetery. There was no "system of burials" until 1862. The Confederates & 41 Federal POW's were buried on a knoll in the cemetery. The exact number of Confederates buried is unclear.