Reading the endnotes to Giovanna Neudorfer's Vermont Stone Chambers, I came across a reference to in Samuel Farmer Jarvis's A discourse on the religion of the Indian tribes of North America (New York Historical Society, 1820). I believe this is note 16 in Neudorfer's book, but the date she gives for it is incorrect; she says 1920, but it is 1820.
On page 106, Jarvis has the following quote from Captain John Smith's book General Historie of Virginia, New England, and the Summer Iles, with the names of the adventurers, planters, and governors, from their first beginning anno 1584 to this point 1625, London 1625 (Jarvis mentions that the quote comes from volume 4, chapter 3 of Smith's book; I'll have to check this):
"They have certaine altar stones, they call Pawcorances, but these stand from their temples, some by their houses, others in the woods and wildernesses, where they have had any extraordinary accident or encounter. As you travel by theam they will tell you the cause of their erection, wherein they instruct their children; so that they are in stead of records and memorialls of their antiquities. Upon this they offer Bloud, Dear Suet, and Tobacco. There they doe when they returne from warres, from hunting, and upon many other occasions."