I don't know much about COBOL, but I did code quite a bit in Fortran. In Fortran, the first five columns were for an optional line number, so these would mostly be blank. The sixth column was a flag that indicated that the line was continued from the one before, this allowed for multiline statements, by default a carriage return was a statement terminator. Like you said, all this came from punch cards.

Columns seven through 72 were for your code