Tillemont conjectures that the drive was to St. Eupsychius, but the day of St. Eupsychius fell in September, which the Ben. note thinks too late for the date of this letter.  The memorials of St. Julitta and St. Gordius were also near Cæsarea, but their days fell in January, which the same note thinks too early.  Gregory of Nyssa (Migne iii. p. 653) says that there were more altars in Cappadocia than in all the world, so that we need have no difficulty in supposing some saint whose date would synchronize with the letter.  Basil, however, may have tried to drive to the shrine of some martyr on some other day than the anniversary of his death.