R.W. Cage was Richard W[ilson?] Cage, son of Wilson J. Cage and Mary Cardwell.He's listed age 11 in the household of Wilson J. Cage in the 1850 Washington Co. AR Census, then as a laborer at age 21 in the hh of P. Stonements in the 1860 Milam Co. TX census, then at age 41 in the 1880 Milam Co. TX census (with wife Mattie B[oyd?] and daughters J.E., Adah? and Ida L.)Mattie Cage (b. MS ca 1854) is listed as a widow in the 1920 Milam Co. TX census.He had a brother, James L. Cage,who also lived in Milam County, and his widowed mother Mary Cardwell Cage lived there as well.
His grandfather was Edward Douglass Cage (1779-1859) of Bedford and Montgomery Co. TN.
I have lots more information on this Cage family, which I'll be happy to swap for your Milam Co. cemetery info.