1847 saw the introduction of the Grimsley saddle for the Dragoons and Mounted Riflemen. the Light  Artillery received the Driver's and Valise Grimsleys for use in harness later. While the 1859 McClellan saw the end of Grimsley use among Cavalry, The Light Artillery used the Grimlseys until finally adopting the Artillery McClellan in 1883. I have ridden and worked on numerous Grimsley saddles, including Dragoon and Artillery patterns.