National Geographic : 1935 Nov
"ON THIS DEITY'S HEAD, THE HARVEST GOD SOWS KERNELS OF MAIZE," EXPLAINS DR. MASON The scene on Stela 40, center, symbolizes fertile fields. The monolith, largest removed from Piedras Negras, weighs five and one-half tons. From this stone Artist Herget painted Color Plate I (see text, page 561). HERE GRAVITY PULLS THE LOAD DOWNHILL; THE YOKED OXEN MERELY GUIDE IT On such steep grades, loaded wagons were snubbed from behind byblock and tackle attached to trees, and lowered gently. One topheavy vehicle turned a complete somersault here and landed upright onitswheels.