Note 462 — Chapter III · STRONGHOLDS.
Reading edition
I know of only one example yet noted out of Scotland, but it is a very remarkable one, and has been thought to confirm the idea of designed vitrification. (Vide Account of the Pierres Brulées, or Camp of Peran, a French primitive fort in the Commune of Clédran. Journal of Archæol. Association, vol. ii. p. 278.) The researches of Mr. Squier and Dr. Davis among the ancient monuments of the Mississippi Valley, reveal various examples of partial vitrification, tending to confirm the more consistent idea of accidental and varying origin.—Smithsonian Contributions to Knowledge, vol. i. pp. 12, 17, 28, 36.