THE GREAT CENTRAL SYNCLINE, 229 



The central fihrolitic mica-schists (the Conway schists). — These are dark, 

 rusty, contorted muscovite-biotite-scliists, at times spangled with transverse 

 biotite. They contain garnets, often in large numbers, of small size and of 

 the form oo (110). Staurolite appears rather rarely, but at localities 

 scattered over all the area, especially on the west, where the Wendell 

 syncline branches off; and across to the east, where the road nortli from 

 Tullyville crosses the town line, the rock is a rather coarse mica-schist, 

 the matrix made up of fine scales of shining-white muscovite, but largely 

 darkened by graphite and by large blotches of biotite. It contains garnets 

 and large single staurolites, together with fibrolite. 



Fibrolite in the mica-schists. — This mineral occiirs in the mica-schist a 

 mile northeast of Warwick Center, south of the house of Rev. J. Goldsbury. 

 If a line be di-awn southeast from this point to the apex of Orange, at the 

 locality just mentioned, above Tullyville, it will mark approximately the 

 northern border of the abundant occurrence of the mineral in the schists. If 

 another line be drawn south from the same point it will mark the western 

 boundary of the occurrence of fibrolite tln-ough Warwick and Orange. From 

 these boundaries it gradually increases in amount southwardly and east- 

 wardly, but the increase is more marked toward the east than toward the 

 south, so that the eastern syncline from its beginning in Tullyville is marked 

 by a maximum of the mineral, which continues clear across the State. It 

 is not abundant in Warwick, nor southward in the central syncline here 

 described, through Orange. The transition is indicated on the map (PI. 

 XXXIV) by allowing the Conway schist color to grade into the Brimfield 

 fibrolite-schist color without di-awing a boundary line across the strike. 

 This is the most important illustration of the passage of the Conway schist 

 into the Brimfield fibrolite-schist. 



To the east of the center of the area of mica-schist occui-s a band of 

 amphibolite, generally porphyritic in ajjpearance, the structure being due 

 to the absence of hornblende from spots which thus appear white. In this 

 amphibolite band is much iron, especially a half mile west of the point where 

 the Warwick-Oi-ange road crosses the town line. Here a small amount of 

 mining work has been done. The mine is opened 2 rods on the "vein" and 

 10 feet deep. The "vein" is a vertical bed of quartz-garnet rock, very 

 fen'uginous, 1 foot wide at north end and 3 feet wide at south end, with a 

 central layer of very compact, pure magnetite 4 to 6 inches thick. 



