BEENAEUSTON SEEIES OP UPPEE DEVONIAN. 261 



upon the rock below. It approaches the arg-ilhte quite closely upon the 

 west, and in the line of strike can not be more than 9,850 feet long. Over 

 against West Mountain on the east, across the narrow valley of Fall River, 

 rises a range of hills, bounded on the south and east by the terrace sands, 

 which is composed of a similar series of rocks in similar succession. The 

 principal difference between the two is that on the east a dark hornblende 

 rock, often massive, takes its place in the series, while the limestone and 

 magnetite beds of the typical section are present only in traces or in altered 

 form, and all the other members are somewhat more metamorphosed. 



Staurolite here occurs in the schists, feldspar ciystals and biotite in the 

 quartzites, and they are thrown into complex folds and greatly faulted. 

 They lie, in fact, along the center of the great syncline of the Connecticut 

 Valley, which is an area of maximum disturbance of the rocks quite across 

 the State. These discrepancies become less important when it is noticed 

 that hornblende exists in considerable quantity directly above the Williams 

 farm limestone, and the second bed of the same limestone in South Vernon 

 is encased in hornblende-schist, and several of the hornblende-schist beds 

 can be proved to be altered limestone beds. 



Across the river in Northfield the white saccharoidal quartzite extends 

 to the base of Northfield Mountain, and is there bounded by a north-south 

 fault, while only a single outcrop of schist is exposed. 



THE RELATION OF THE BERKARDSTOIS" SERIES TO THE ARGILLITE. 



It was originally assumed by President Hitchcock that the argillite 

 and the schists of this series were conformable. Prof. J. D. Daua,^ finding 

 the argillite about a half mile west of the limestone to have a much higher 

 dip, decided that they were unconformable to and much older than the 

 upper series, and this conclusion was accepted by Prof C. H. Hitchcock." 

 In tracing the distribution of the quartzite, I have given five localities where 

 the boundary of the quartzite and argillite is well exposed (j). 273), and I 

 could increase the number, and in each case there is apparent conformity 

 and a uniform passage from the common argillite into argillite with minute 

 garnets and minute biotite spangles, fine-grained black quartzite grading 



'Am. Jour. Sci., Vol. VI, 3d series, 1872, p. 343. 

 2Geol. New Hampshire, Vol. II, 1887, p. 433. 



