On these shelves, also, were many quaintly wrought vessels and some small square boxes, all of which were of gold—together with a score or so of small idols moulded in clay or roughly carved in stone, in which last the workmanship was so far inferior to that of the earthen-ware pots and golden vessels as to show at a glance that they were the product of a much earlier and ruder age; but belonging to the same age as the gold-work, or to a period even later, was a very beautiful Calendar Stone most delicately carved in obsidian, that was identical, save in the matter of size, with the great Calendar Stone that now is preserved in Mexico in the National Museum.
— from The Aztec Treasure-House by Thomas A. (Thomas Allibone) Janvier