Noticed your reference to Army/Marines in The Great War—here is a tidbit of history from a webpage I did on WW I Marines and Army—as mentioned, Marines did command Army units, but Army officers also commanded Marine units; and, in at least one case, an army officer even wore the Globe and Anchor emblems while commanding Marines!
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“WORLD WAR ONE MARINES
“Pershing was mercilessly thinning the ranks of senior officers he considered too old or infirm for field command. Brigadier General Doyen was one of the casualties. He was invalided home and replaced by a Pershing favorite, Army Brig. Gen. James Harbord. Harbord had been Pershing’s chief of staff and he had gone from major to brigadier general in a year. Col. Buck Neville, now the commander of the 5th Marines and far senior to Harbord at the war’s beginning, had every reason to think that he should have been given command of the brigade. On Harbord’s arrival, when Neville handed him a pair of Marine Corps emblems, it was half a greeting, half a challenge. Harbord promptly put them on his collar....On Bastille day, 14 July, Harbord, a jaunty hybrid in his poilu’s helmet and Marine emblems, moved up to command of the 2d Division. Buck Neville took over the Marine brigade and would soon be promoted to brigadier general.”
-Simmons
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Since you are familiar with both Army and Marines, thought this may be of interest to ya...
Best Wishes
Dick Gaines
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I’ll “support” them by kicking their useless asses. Semper Fi!