Doyle
I did some checking and found some reference's to uniforms made of penitentiary cloth, which was osnaburg.
Also, from the 1 Febuary, 1864 Galveston Tri-Weekly News, an account for manufacture from 12-1-61 to 12-18-63, Huntsville Prison;
Osnaburgs 2,259,385 yards
Cotton Jeans 409,047 yards
Wh. Kerseys 242,022 yards
White Plains (wool jean) 78,103 yards
Sheep Gray (wool jean) 40,391 yards