At UNC stadium's 1927 dedication (and second) game, the endzone was marked with "horizontal" stripes, but they weren't centered. Only one goal line that year, and the horizontal stripes never returned. Subsequent seasons saw a second goal line added. https://flic.kr/p/25n7Lfx
Various stadiums had the slanted stripes in the end zone, but Springfield Teachers is the first I came across that marked part of the field like UNC did the end zones.
At UNC stadium's 1927 dedication (and second) game, the endzone was marked with "horizontal" stripes, but they weren't centered. Only one goal line that year, and the horizontal stripes never returned. Subsequent seasons saw a second goal line added. https://flic.kr/p/25n7Lfx
Various stadiums had the slanted stripes in the end zone, but Springfield Teachers is the first I came across that marked part of the field like UNC did the end zones.