1()(; tJi;oLO(;Y or old UAMrsHiitE county, mass. 



This is well seen in going east from the Hiiwley iron mine. West of the 

 ore bed the roek is the connnon quartzose sericite-schist (Savoy). The ore 

 l)e(l itself is a lieniatite-sehist (itahirite), made up of beautifully corrugated 

 seali's of niieaeeous hematite, which can be followed on the strike more than 

 a mile. The pure hematite reaches .scarcely a foot in thicknes.s. Includ- 

 ing the (luartz-heraatite-schist the visible thickness was not above 3 feet, 

 but from the width of the open workings of the bed, now filled with Avater, 

 the thickness would seem to have l)een in places more than twice as nuich. 



(Joing east down the long hillside, and with the dij) of the steeply 

 inclined beds, one linds a great thickness of chloritic schists, so al)0unding 

 in yellow ankerite in grains that the latter mineral often makes more than 

 half its mass, and near the surface, where it is weathered out, the rock is 

 often a friable mass, somewhat rusty. At the foot of the hill is a gi-eat 

 development of aniphibolite, and much of the sericite-schist abounds in the 

 sheaf-like hornblende aggregates or fasciculite, and this description holds 

 true clear across the town to the upper boundary of this series. North 

 through Oharlemont and Rowe to the State line great beds of chlorite-schist, 

 <iften dolomitic, and of hornblende-schist, sometimes Avith calcite, abound 

 (as just west of Oharlemont station), and the sericite-schist itself is often a 

 fasciculite-schist. 



PETKOGRAI'HICAl. DF.SCRIPTION. 



The jet-black, thiu-tissile hornblende-schists of this series do not 

 materially differ from those found below. Two specimens were chosen for 

 special microscopical examination, and one of these has also been analyzed. 



Porpliyritic epidote-ainphiholite from northeast of E. Gleason's, Heath 

 (see PI. VI, fig.3, ]).30G). A dull-black, iissile rock made up of matted needles 

 visible to the eye, doubly porpliyritic, with black, stout hornblendes and long, 

 rectangular, wliite plagioclase crystals with greasy luster from the abundant 

 epidote inclusions. With common light the stout hornblende sections show 

 a ])eculi;u- ilichroism. The basal sections sire of a yellow color, similar to 

 that shown l)v the same sections with polarizcil light vibrating parallel to 

 (f, and the longitudinal sections a green like that seen [)arallel to c. They 

 have a clear border, but the center is so full of inclusions as to give a 

 mosaic of bi-illiant color. Small hornblendes, epidote, biotite, and ankerite 

 abound. The hornblendes are twinned, with extinction 21° on either side 

 of the suture, and show strong absorption colors: .c = blue, b = olive-green, 



