"Hash-Mark"

[GyG1345]

I find it interesting that the adoption of the hash-mark as an item of uniform made its entry into the Marine Corps in 1833, not as a service stripe, as it was later, but as an insigne of rank (on the fatigue uniform)--sergeants and corporals wore two stripes and one stripe respectively below the elbow. The designations prevailed until 1859.

Ref
Enlisted Rank And Grades, 1775-1958, by Bernard C. Nalty, Historical Branch, G-3, Headquarters, U.S. Marine Corps, washington, DC, June 1959

[greensideout]

And I thought it's origin was below the belt line-----never mind.

[SHOOTER1]

greensideout, you were thinking of Skidmarks.