In 1903 some businessmen in Mexico recognized the quality and uniqueness of the fire clay in the area. They raised money and established the Mexico Brick and Fire Clay Co. In 1910 they sold it to a young engineer named A.P. Green. In 1915 he incorporated as the A.P.Green Fire Brick Company. By 1937 it was said to be the world's largest fireclay plant. In 1930 a young man named J.B. Arthur left Green's to form his own company, the Mexico Refractories Co. Other companies came in and by the 50's Audrain County was known as the "Fire Brick Capital of the World". Brick from Green's was used to make the first launching pad at Cape Canaveral.
Mexico Refractories brick was stamped Mex-R-Co. Mexico Refractories was bought by Kaiser Refractories (I think in 1959) and is now a part of NRMC. Green's was bought originally by U.S. Gypsum and I think is now owned by RHI Refractories