Marcus married Eva Atwood circa 1911. Sometime between Eva's 1933 death and the 1940 US Census enumeration he married Ellen M_ _ _ _ (circa 1903-1986.) Marcus worked in various capacities for a tent manufacturer.
Information re: plot and inscription came from survey by Maggie Rail, 2001-2012 mrail.net/data/cemete/wash/ spokane/greenwood/index.htm
Additional information was taken from US Census enumerations for 1900 (with parents and siblings in Hell Gate, Missoula, Montana,) 1910 (with parents and siblings in Spokane, Spokane, Washington,) 1920 and 1930 (with spouse (Eva) and daughters in Spokane, Spokane, Washington,) and 1940 (with spouse (Ellen) in Spokane, Spokane, Washington;) World War I and II draft registration cards; Washington Death Certificate 010459; Social Security Death Index; and Washington Death Index, 1940-1996 (Certificate 004808, re: wife Ellen.)
Contributor #46805729 has suggested that Marcus married Eva Atwood on October 13, 1911 in Spokane, and Ellen Mae Miner on May 6, 1939 Pend Oreille.