O.D.WALQ0TT. 



THE 



AMERICAN JOURNAL OF SCIENCE 



[THIRD SERIES.] 



Art. XXXY. — A description of the " Bernardston Series'''' 

 ■ of Metamorphic Upper Devonian Rocks / by Ben K. 

 Emerson.* 



■ 1. Description of the Region. — The terrace sands of the 

 Connecticut river are narrow upon its western side where the 

 river crosses the State line, and they continue with little increase 

 of width for four miles southwesterly, and then, as they enter 

 Bernardston, their boundary upon the older rocks turns abruptly 

 west, and runs for seven miles a little south of west, past the 

 village of Bernardston, and along the north line of Greenfield. 

 Bernardston village stands just in the middle of this line, and 

 at the mouth of a narrow valley, up which a lobe of the alluvial 

 sands reaches northwardly for nearly two miles. On the west, 

 this valley is bounded by the high ridge of West Mountain, 

 made up of the contorted argillite which stretches in a narrow 

 band far north, across Vermont, and disappears below the river 



* The~ introductory part of this paper, giving a history of previous investigations 

 in the region, is here omitted. The publications mentioned in it, which are of 

 chief interest in this connection, are: Prof. Edward Hitchcock's Report on the 

 Geology of Massachusetts, 1833, and 2d ed. 1835, the latter mentioning the dis- 

 covery of Crinoids and giving figures ; the Report on the Geology of Vermont, 

 bv E. and C. H. Hitchcock, i, 447 and ii, 598, 1861 ; the two papers of J. D. 

 Dana in' this Journal. Ill, vi. 339, 1873, and xiv, 379, 1877; a paper by C. H. 

 Hitchcock in this Journal, xiii, 313, 1877; also observations by C. H. Hitchcock 

 in the Geology of New Hampshire, ii, 428, 1877 ; a short paper by R. P. Whitfield 

 on the fossils of Bernardston, based chiefly on specimens of new forms discovered 

 by Prof. Emerson, published in this Journal, xxv, 368, 1883. 



The investigation by Prof. Dana had in view the chronological panon with 

 regard to crystalline rocks — that kind of rock was a safe criterion of geological 

 age — and that, under it, " staurolite crystals were as good as fossils " for the 

 purpose. The metamorphic Taconic region of western New England, and the 



Am. Jour. Sci— Third Series, Vol. XL, No. 238.— Oct., 1890. 

 17 



