ALGONKIAN ROCKS IN VERMONT. 4OI 



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. ^ Under the head 

 of Azoic Rocks, ^ Charles H. Hitchcock places the Ver- 

 mont 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 Lingular 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 con- 

 glomerate." ■♦ 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 cor- 

 relation 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 



'Geology of Vermont, 1861, 2 volumes. 



^Opus. cit. Vol. I., pp. 452 to 453. 



3 Opus. cit. Vol. I., p. 500. 



^Opus. cit. See geological map of Vermont. PI. I., Vol. I. 



