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ALGONKIAN ROCKS IN VERMONT.
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formation * * * ." The gneiss of the Green Mountains is by him and by the geological survey of Canada referred to the Quebec group and a synclinal structure is assigned to the range probably largely on the basis of the views of Thompson. It is thus seen that Adams' suggestion of the anticlinal nature of the mountains and their "primary" age are passed over, as well as the more recent work of the elder Hitchcock, to which reference is made below.

Anything like a close study of the Green Mountains was not attempted until 1861, when the two Hitchcocks finished their work on the geology of the state.[1] Under the head of Azoic Rocks,[2] Charles H. Hitchcock places the Vermont rocks occurring east of the Stockbridge limestone as far as the Connecticut river, and includes therein the basal quartzite of Emmons' Taconic system, although the elder Hitchcock admits finding therein traces of life in the shape of Scolithus and a species of Lingula[3] which were not deemed sufficient evidence to warrant classifying this horizon with the fossiliferous rocks. The younger Hitchcock divided the azoic rocks as follows: Gneiss (Adams' Green Mountain Gneiss) hornblende schist, mica-schist, clay-slate, quartz-rock, talcose schist, serpentine and steatite and saccharoidal limestone. The most western member, the quartz-rock or quartzite with its associated conglomerate is mapped as extending the whole length of the state. Just north of the area studied by me it is represented as thinning out and giving place to "talcose conglomerate."[4] On the east side of the mountains a narrow strip is colored in extending through the towns of Plymouth and Ludlow. Lithological similarity is used as a basis for the correlation of the conglomerate, which underlies the "quartz-rock" at Wallingford with the Shawangunk Grit or Oneida Conglomerate of New York. The quartzite or quartz-rock is referred for

  1. ↑ Geology of Vermont, 1861, 2 volumes.
  2. ↑ Opus. cit. Vol. I., pp. 452 to 453.
  3. ↑ Opus. cit. Vol. I., p. 500.
  4. ↑ Opus. cit.See geological map of Vermont. Pl. I., Vol. I.
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