286 GEOLOGY OF OLD HAMPSHIRE COUNTY, MASS. 



chauges to a gneiss so complete that Professor Hitchcock insists on associ- 

 ating it with the Bethlehem gneiss — quartzite with flattened pebbles, mus- 

 covite-quartzite, biotite-quartzite, feldspathic quartzite, often porphyritic, 

 and complete biotite-gneiss, often becoming chloritic from superficial change. 



The limestone has become most coai-sely crystalline and the lime and 

 iron have been carried far out into the quartzites above and below, to form 

 amphibolites and complex hornblende-chlorite-pyrite rocks. The iron ore 

 forms a bed of magnetite or a magnetite rock, probably precipitated as 

 limonite at the surface of the limestone in the earlier stages of change, and 

 then metamorphosed to magnetite later. 



The upper series is changed to complete mica-schists, spangled with 

 transverse biotite crystals, often loaded with garnets and staurolites, while 

 the limestone beds are changed from the surface toward the center into 

 amphiliolite beds, abstracting the iron from an adjacent band of the shales. 



The dips are all to the east and the beds are several times repeated by 

 monocliual faulting, and mtli each reappearance of the quartzite it is finer- 

 grained and more feldspathic. 



The series has a slight pitch to the south, so that in Vernon the whole 

 upper series tapers northward and disappears; and then in going east- 

 ward from the argillite we pass from the more quartzose conglomerates 

 thi'ough muscovite- and biotite-quartzite to complete gneisses, as in the 

 successive reappearances farther south. 



The most abundant and characteristic fossils are Chemung with several 

 Hamilton forms, so that the limestone, magnetite, and the base of the quartz- 

 ite above the limestone niay be placed with certainty near the base of the 

 Chemung. That the whole series must go together is, I think, clear from 

 the map and the preceding discussion. The suggestion of Professor Hitch- 

 cock that the limestone was bounded on both sides by faults^ proves trae 

 for the west side, but it is not true for the east side, and the important 

 deduction made by him that the limestone was much newer than all the 

 surrounding rocks is also fhsproved." 



'Am. Jour. Sci., 3d series, Vol. XIII, 1877, p. 315. 



^Professor Hitchcock informs me by letter of November 22, 1890, that he did not speak of two 

 faults, as implied above, but held that the limestone was newer than the quartzite and infolded in it. 

 A reference to the article above cited proves that no mention is made of faults, and I am at a loss to 

 explain how I came to refer this opinion to Professor Hitchcock when the above paragraph was printed 

 by me in the American .Journal of Science in October, 1890, p. 374. That the limestone is newer than 

 the quartzite is, however, clearly untenable. 



