Page:Geological Evidences of the Antiquity of Man.djvu/379

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CHAP. XVIII.
DOME-SHAPED ERRATIC.
359

I observed one of the green blocks, twenty-four feet long, poised upon another about nineteen feet in length. The largest of all on the west flank of m, or Dupey's Mount, called the Alderman, is above ninety feet in diameter,

Fig. 51

Geological Evidences of the Antiquity of Man Fig. 51.png

Erratic dome-shaped block of compact chloritic rock (n map, fig. 50), near the Richmond Meeting-house, Berkshire, Massachusetts, lat. 42° 25′ N. Length, fifty-two feet; width, forty feet; height above the soil, fifteen feet.

Fig. 52

Geological Evidences of the Antiquity of Man Fig. 52.png

Section showing position of the block, fig. 51.

a The large block. Fig. 51 and n map, p. 357.
b Fragment detached from the same.
c Unstratified drift with boulders.
d Silurian limestone in inclined stratification.

and nearly three hundred feet in circumference. We counted at some points between forty and fifty blocks visible at once, the smallest of them larger than a camel.