School Bag Clutch, circa 1974
Style 9390
Shown in: White
This style did not come with a strap, but a variation released in 1976 did-- this version was also called a School Bag Clutch, though it bore a different style number (style 9390 in 1974, and style 9515 in 1976).
Photos courtesy of @shopcristinamoda
Scan from the Fall 1974 catalog
Ad from 1976 showing the reintroduced version that included a removable shoulder strap