Man, I'm a pretty old dude, and I've never seen or heard of that grading scale before. Is it possible that was unique to your school? That seems pretty rigorous.
In all my years and experience with schools in several different states in the North and South, I've only ever experienced the scale mentioned by Photonguy. The more exotic ones would add plusses and minuses, and in Seattle public schools, they used E instead of F.
As someone who was perpetually at night school and summer school anyway, I'm really glad that 60 and above was passing, or I might never have graduated.