THE CONWAY SCHISTS. 195 



amphibolite, easily mistaken for the bituminous shale, and exactly resem- 

 bling the above amphibohte, especially iu having the highly vefriugent 

 grains, each inclosing one or more rounded grains of a dark ore, which is 

 here slightly bi'ownish. The agreement, macroscopic and microscopic, is 

 so perfect, and the rock is chemically so nearly identical with the Guilford 

 band of amphibolite iu the Conway schist farther north, as shown by the 

 analyses below, that one can not doubt that the WTiately amphibolite is 

 continued in the line of its strike northeast beneath the sandstone to the 

 Whitmores Feny outcrop.' The association with whetstone-schist in both 

 places strengthens the probability of their identity. 



The agreement of the three analyses given below is sufficiently close 

 to strengthen the opinion maintained above that all these horublendic rocks 

 have been derived from limestone beds. 



(h) The Guilford band. (For section, see PI. VI, fig. 2, p. 306). An 

 inspection of the map (PI. XXXIV) will show this extensive bed, beginning 

 in Conway and ranning continuously across the northern half of the State 

 and widening suddenly as it crosses into Vermont. Its stratigraphical 

 relations do not preclude the supposition that it may be a great dike. Lith- 

 ologically it is like many beds of the Chester and Hawley series. Its 

 cleavage sm-faces show many black hornblende needles of high luster iu 

 a mat of finer needles. Its hornblende crystals are not filled with gi'ains 

 of coal or earlier constituents, as are the other Conway beds, and also 

 the Bernardston beds. The most marked peculiarity of this band is the 

 presence in the slide of many deep red-brown rutiles clustering around 

 black ore grains. The feldspar seems to be albite, with which the content 

 of soda agi-ees. 



ANALYSES OF THE AMPHIBOLITES. 



I. Guilford, Vennont. Shining-black, thin-bedded amphibolite. 



II. ^^Hiitmores FeiTy, Sunderland. Outcrop in the midst of the Trias. 

 Very fine-grained, dull-black, shaly amphibolite. 



III. Goshen. Base of largest "an\al," from which slides described 

 above (p. 191) were taken. A quartz-homblende rock, formed by the alter- 

 ation of the limestone by reaction of solutions derived from the inclosing 

 schists. For general discussion of analyses see page 300. 



' See p. 361. 



