The Green Mountain Giant is a glacial erratic in Whittingham, VT. A glacial erratic is a boulder transported and deposited by a glacier and is different than the rock on which it sits.
The boulder is described in Hitchcock, E. et.al, 1861, in Report on the Geology of Vermont: Descriptive, Theoretical, Economical, and Scenographical Vol.1: The Claremont Manufacturing Company, Claremont, NH on p. 58-59......
“But the most gigantic specimen with which we have met, lies on the naked ledges on a high hill on the farm of Jonathan Dix, in the west part of Whitingham. From this hill we look westerly into the valley of the Deerfield river, which must be over 500 feet deep, and from the character of the rock, corresponding to that of the Green Mountains (a highly micaceous gneiss), we feel sure that the bowlder was transported across this valley. yet its length is 40 feet; its horizontal circumference is 125 feet; its average width 32 feet; its cubic contents 40,000 feet, and its weight 3400 tons. Think of the power requisite in the first place to tear off from the ledge such a gigantic mass, and then to lift it up and carry it across a deep mountain valley, and then to plant it near the highest part of a rocky ridge. it does not seem to have been much rounded, and cannot therefore have been subject to mere mechanical or aqueous attrition. hence we suppose it to have been lifted up bodily and transported- not rolled – along with other fragments by a vis a tergo. The sketch below will give some idea of one of the sides of this bowlder. An end view is quite different. it is situated in the midst of a forest and a little southeast of and below the crest of the hill.
Until a larger bowlder shall be found, we propose for this one the name of Green Mountain Giant. It is the largest we have met with in New England, save one at Fall River – which is now destroyed for architectural purposes. The Giant should have a ladder attached to it, and the forest around it be cleared away, that persons of taste might be induced to visit it. Such objects are beginning to be incorporated into the world’s literature, and we already have at least one volume entitled “The Bowlder,” as well as Hugh Miller’s Autobiography of a bowlder. Ere many years we predict that the Guide Books for summer tourists will describe the route to the Giant. When that shall happen we would recommend that those who visit it should extend their tour on the road from Whitingham to Hartwellville in Readsboro, to where it crosses the Deerfield river at Readsboro Hollow, where they will find the bowlders very numerous and large. Under the bridge across the Deerfield river lies one 25 feet long and 15 feet high, which weighs 478 tons, about equal to the largest in Great Britain.”