BEENARDSTON SERIES OF UPPER DEVONIAN. 277 



five — of hornblende rock, a massive iunpliil)olite, and a central band of 

 gneissoid quartzite. From the unequal rigidity of these rocks thoy are 

 thrown into gx'eat confusion, and from the similarity of the rock in the sep- 

 arate bands the tracing of them is very difficult. As they ai'e placed xq:)on 

 tlie map a greater regularity appeal's than exists in the field, m;uiy bands 

 being made up of the slightly shifted portions of what was originally one, 

 and many minor fixults being of necessity neglected. 



In general the schist is in its lower portions finer-grained and more 

 slaty, with small development of the transverse mica, without staurolite, and 

 with quite small garnets, becoming above coarser, of rougher surface, and 

 knotted Avith large staurolites. 



At the south end, nearest the Williams farm, along the road east of 

 Fall River and northeast of Bernardston village, the basal (junrtzite dips 

 beneath a very fine-grained, flat-fissile mica-slate, which dips 20'' in the 

 direction S. 10° E., its surface sparsely pimpled with small garnets, but 

 being without other accessories and closely like the western schist (!') 

 of the Williams farm section. A local bed of a dark, ^^yritous quartzite, 

 slightly hornblendic, is marked in this band of schist, but could not be 

 followed far east. 



The lowest bed of amphil)olite is followe<l by a second biuid of mica- 

 slate exactly like the first, which widens in outcrop easterly and passes with 

 the same dip and strike beneath a massive, dark-gray to greeni.sh-black 

 amphibolite, greatly jointed, and this is exposed in a broad area nearly down 

 to the main road running east from l^ernardston and extending east to the 

 house of S. J. Green, 100 rods west of the locality mentioned by Professor 

 Dana.^ It contains a central band of dark limestone, at times a foot thick. 

 The amphibolite is capped by a thin layer, never more than 3 feet thick, of a 

 shining-white, arenaceous mica-schist, with scattered scales of biotite, and a 

 similar layer was foun<l to cap a similar hornblende rock in so great a number 

 of instances between tliis j)oint and South Vernon that it attracted particular 

 attention. This white layer was found to pass in every case up into the 

 common dark-gray mica-schist, and to differ from it only in the entire absence 

 of coaly matter and magnetite ; and it seems possible that the former may 

 have been discharged by the feiTuginous matter of the hornblendic band 

 adjacent; that is, the organic matter may have been employed to reduce 



'Am. Jour. Sci.. 3d series, Vol. VI, 1873, p. 342. 



