A variation on the 19th-century slab serif, AKA antique, but with bracketed serifs. Ionic is an older term.
“Though technically a 19th-century innovation — Figgins included brackets on a set of capitals in 1833, Caslon followed with a bracketed lowercase in 1844, and Benjamin Fox produced the first face called Clarendon for the foundry of Thorowgood and Besley in 1845” — Hoefler & Co.
The Clarendon we know best today is Hermann Eidenbenz’s 1953 adaptation for Haas.
