The Canadian Football League formally broke from the Canadian Rugby Union in 1958 and developed rules more along the lines of American Football.
The differences are Canadian Football is 12-a-side and played on a bigger field (110 yards long & two 20 yard endzones, and also wider), and there is also only three downs to gain 10 yards before the ball is turned over. Scoring includes a ‘rouge’ – a single point scored when the ball is kicked out the back of the endzone but not between the posts.
Canadian Football League:
Canadian Junior Football Leagues:
Canadian Rugby Union (1947-1966):