As far as I am aware, there is no such thing as a Clogston crest. Clogston is an alternate spelling of Clugston, which is the name of a town in Scotland near Wigtown. The Clugstons where a sept of the clan Dunbar which has a tartan and a crest. The crest is a horses head in a bridal with In Promptu written above it. More information on clan Dunbar can be found on the web fairly easy.