Nicene and Post-Nicene Fathers, Vol. IV:
Writings in Connection with the Donatist Controversy.: Chapter 31

Chapter 31.—60.  Tenax of Horrea Celiæ 1842 said:  "There is one baptism, but of the Church; and where the Church is not, there baptism also cannot be." 1843

61.  To him we answer:  How then comes it that it may be where the rock is not, but only sand; seeing that the Church is on the rock, and not on sand?

Footnotes

Horrea Celiæ (Cæliæ) was a village of ecclesiastical province of Byzacium, ten miles north of Hadrumetum.  A Tenax is mentioned as bishop in Cypr. Ep. lxvii.

Conc. Carth. sec. 67.