Note 18 — Chapter XIV · 1521.
Reading edition
See Trans. Amer. Ethnol. Soc'y., vol. 1, p. 94. We should remark that the letters Q. Q., X. Z., P. P., S. Y., on the edge of the stone, denote holes cut into it, in which it is asserted that gnomons were placed whose shadows on the calendar converted it into a dial.