1977 Low 7 date - the top of the last 7 is below the top of the first 7 .
1977 Low 7 date - the top of the last 7 is below the top of the first 7 .
1977 High 7 date - the top of the last 7 is above the top of the first 7 .
The images are from Joe Kennedy (benderbot@excite.com).