363. Baehrens would put the lower limit at 63 A. D., the year in which severe earthquakes first indicated the reviving activity of Phlegraean fields. But earthquakes, though often caused by volcanic action, do not necessarily produce volcanoes.
364. viii. 16. 9; 10. 185.
365. iii. 3. 3 'his certe temporibus Nomentana regio celeberrima fama est illustris, et praecipue quam possidet Seneca, vir excellentis ingenii atque doctrinae'. He is quoted by Pliny, not infrequently. Columella was an old man when he wrote; cp. 12 ad fin. 'nec tamen canis natura dedit cunctarum rerum prudentiam'.
366. Cp. C.I.L. ix. 235 'L. Iunio L. F. Gal. Moderato Columellae Trib. mil. leg. VI. Ferratae'. That this refers to the poet is borne out by two facts. (1) Gades belonged to the Tribus Galeria. (2) At this date the legio VI. Ferrata was stationed in Syria; cp. Col. ii. 10. 18 'Ciliciae Syriaeque regionibus ipse vidi'.
367. Cp. i. 1. 7. He speaks as a practical farmer; cp. ii. 8. 5; 9. 1; 10. 11; iii. 9. 2; 10. 8, &c. He writes primarily for Italy, not for Spain; cp. iii. 8. 5.
368. Cp. x. praef.: also ix. 16. 2, which tells us that Gallio, Seneca's brother, had added his entreaties.
369. xi. praef.
370. He also wrote a treatise against astrologers (cp. xi. 1. 131) and a treatise on religious ceremonies connected with agriculture (cp. ii. 21. 5). This latter work was perhaps never completed (cp. ii. 21. 6). In any case both treatises were lost. There survives a book on arboriculture which is not an isolated monograph, but portion of a larger work, at least three books long, for it alludes to a 'primum volumen de cultu agrorum' (ad init.). It probably consisted of four books, since Cassiodorus (div. lect. 28) speaks of the sixteen books of Columella.
371. siderei Maronis, 434.
372. Cp. esp. 196 sqq.