Coat of arms of the U.S. bishop George Leo Thomas, Bishop of Helena.
Blazon: Arms impaled. Dexter: Chevronny of eight Argent and Vert, a Latin cross, the terminations patty, enfiling in fess an open crown Or. Sinister: Argent, upon a cross Azure, a Paschal candle Proper; between; to chief dexter a pick and shovel in saltair Vert and to chief sinister a Keltic “M” of the second; and in base two garbs of wheat Proper.
Motto: “CHRIST OUR LIGHT”.
Reference:

www.diocesehelena.org
Own work
SajoR