B. K. Emerson — " Bernardston Series" etc. 267 



saccharoidal quartzite extends to the base of the JNorthfield 

 Mountain and is there bounded by a north-south fault, while 

 only a single outcrop of schist is exposed. 



2. The relation of the Bernardston series to the Argillite. 

 —It was originally assumed by President Hitchcock that the 

 argillite and the schists of this series were conformable. Pro- 

 fessor J. D. Dana,* 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.f I have, 

 in tracing the distribution of the quartzite, given five localities 

 where the boundary of the quartzite and argillite is well exposed, 

 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 graduating into coarser 

 quartzite and conglomerate. The argillite is extremely corrugated 

 and often cleaved, and observations of dip a rod from the contact 

 are of no value as settling a question like this. 



3. The Williams Farm Section. — See maps 1 and 2 and 

 sections, figs. 3, 4, 5. The long band of the rocks of the Ber- 

 nardston series along the lower slope of the West Mountain 

 has been brought into its present position by extensive dislo- 

 cations and is plainly cut by two transverse faults which run 

 approximately with the brook gorge north of the limestone and 

 with the larger gorge of Fox brook half a mile south. The 

 area between containing the fossiliferous limestone is the one 

 here described. 



Passing up the hillside, back of Mr. Williams's barn, the first 

 bed and the upper one on the section (fig. 3) is a dark musco- 

 vite schist, which is exposed in a single small quarry and sepa- 

 rated by a depression which runs with the strike, and which I 

 have supposed in the section to be occupied by the same schists 

 and to have been formed by their erosion. The outcrops are 

 almost continuous across the quartzite and limestone which 

 follow, to the second outcrop of schist, where a similar depres- 

 sion separates the latter from the second band of quartzite, 

 which I have in like manner supposed to be occupied by this 

 schist. The thicknesses given in the section are, with this 

 explanation, the result of careful measurement ; and the eleva- 

 tions taken with two closely agreeing aneroids, and referred to 

 the sea level by means of the height of the railroad station 

 at Bernardston, corrected so as to agree with Gen. Ellis's survey 

 of the Connecticut Piver. 



* This Journal, III, vi, 343. f Geol. N. H., ii, 433, 1887. 



