Which of the following is NOT true concerning the dentate line of the anal canal?

The rectum contains columnar epithelium and this is replaced by a transition zone in the upper anus, consisting of a combination of columnar and squamous epithelium. This is the area that corresponds with the embryonic fusion of the hindgut and the proctodeum. The dentate line is the junction at the level of the anal valves. Above the dentate line lies the columns of Morgagni which end in the anal valves. Caudal to the dentate line the anus is lined by only stratified squamous epithelium. Ref: Moon D.A., Foreman K.B., Albeine K.H. (2011). Chapter 12. Pelvis and Perineum. In D.A. Moon, K.B. Foreman, K.H. Albeine (Eds), The Big Picture: Gross Anatomy.