[As for] the earth, out of it cometh bread,.... That is, bread corn, or corn of which bread is made particularly wheat; which falling, or being cast into the earth, rises up and brings forth fruit, and, when ground into flour, makes fine bread; and to this same original the psalmist ascribes bread, which strengthens man's heart, Ps 104:14.
The West Indians formerly made their bread of roots of the earth, particularly one called "jucca" ; so Caesar's soldiers in distress made bread of a root called "chara", steeped in milk :and under it is turned up as it were fire; coal, which is fuel for fire; for, as in the earth are mines for gold and silver, iron and brass, out of which they are dug, or the ore of them, so there is coal under the earth; which, when turned up, or dug, is taken for firing; or brimstone, or sulphureous matter, which is easily inflammable; and sometimes the same earth, the surface of which is covered with corn, out of which bread cometh, underneath are coal, or sulphur, and such like combustible matter: some think precious stones are meant, which glitter and sparkle like fire; see Eze 28:14.
P. Martyr, Decad 1. l. 1. Caesar. Comment. Bell. Civil. l. 3. c.