BERNARDSTON SERIES OF UPPER DEVONIAN. 289 



leucoxene. There are many carlsbad twins and one very distinct case of 

 secondary growth of a rounded grain of feldspar. 



7. A fine-grained, pepper-and-salt gneiss, slightly more granitoid and 

 feldspathic than the above, from West Nortlifield, on section west from 

 South Vernon fair grounds, inteiTupting second hornblendic band. It con- 

 tains the same constituents, together with grains of plagioclase, with the 

 extinction uniformly 3i-4° on either side of the twinning plane. The 

 orthoclase is more abundant, larger, wholly xenomorphic, and never 

 twinned; it cements many quartz grains together. Leucoxene gi'ains con- 

 tain centers of ilmenite, and many grains of black ore appear. 



8. Micaceous limestone from AVilliams farm, just above the magnetite 

 bed at the opening where it is thickest. A black, compact I'ock, rusting red 

 and ghstening under the lens with tine biotite scales. 



Under the microscope this is a granular limestone composed of sub- 

 angular, equal-sided grains of calcite, many polysynthetically twinned. 

 Biotite is regularly disseminated through the mass without ]>eing orientated 

 to any plane, much as it is in the whetstone-schist, to whicli rock the one 

 under examination bears a close resemblance in its microscopical appear- 

 ance. This biotite is of so deep absorption that basal sections are wholly 

 opaque except at the thinnest edge of the section, and then greenish-brown. 

 A single crystal of hornblende and a little magnetite and rust appear. An 

 arm piece of a crinoid was seen, and fragments of the punctate shell of a 

 brachiopod, in which the centrally expanded center of the pores can be 

 detected. 



9. Biotite-quartz-schist from Williams farm, at bluff overlooking brook 

 at north end of limestone and directly overlying tlie latter where excavation 

 was made to expose the fault. A rusty, thin-bedded, dark biotite-schist 

 with much biotite appearing in the granular quartz mass and minute, white, 

 square needles on foliation faces; no effervescence. 



In section a granular clastic quartz ground run through by veins of 

 secondary granular quartz with gi-ains larger than those in the mass, the 

 whole swarming" with flakes and shreds of dark-brown biotite much notched 

 at the edges. Menaccanite sun*ounded by leucoxene, pyrite, and the jDrob- 

 lematical needles. These are long needles with longitudinal and transverse 

 cleavage and longitudinal extinction; refraction strong. They are red- 

 brown,* with faint pleochi-oism down the center and bordered by a nairow 



MON XXIX 19 



