Well, if you are talking about C.M.Russell or CMR in Great Falls, Montana. The skull is of a cow. It was one of the first things Charlie saw when looking out of his train and from then on he would put the skull by his name in every picture and that became the school's logo or symbol.
A. C. Reynolds High School was created in 1955.
Baliati I. C. High School was created in 1919.
William C. Hinkley High School was created in 1973.
C. Milton Wright High School was created in 1980.
C. D. Hylton High School was created in 1991.
C. Leon King High School was created in 1960.
C. E. Byrd High School was created in 1924.
Adrian C. Wilcox High School was created in 1961.
Edward C. Reed High School was created in 1974.
E. C. Glass High School was created in 1871.
Tom C. Clark High School was created in 1978.
John C. Kimball High School was created in 2009.