CHAPTER VII. 



THE GRAPHITIC MICA-SCHIST SERIES ON THE WEST SIDE 

 OF THE VALLEY. 



THE GOSHEN SCHISTS OR FLAGS. 



The Goshen schist includes the lower portion of the " calcareomica 

 slate" of Prof C. B. Adams, or the "calciferous mica-schist" of the Second 

 Vermont Survey.^ The second name is objectionable, because it is used in 

 England for a subdivision of the Carboniferous and in America for a sub- 

 division of the Silurian; and in the uncertainty concerning the age of the 

 beds here described mistakes have arisen, and it has been supposed that the 

 name carried with it an implication that the rocks were Lower Silurian. 

 Moreover, the name as usually employed would indicate that calcite was 

 an accessory constituent of the rock, and not that beds of limestone were 

 intercalated at wide distances in the series. This latter is the case, and in 

 central Massachusetts they are so widely separated that generally only two 

 or three thin beds occur in a township, and in the lower subdivision here to 

 be described they are almost wholly wanting. The limestone grows far 

 more abundant northward across Vermont. 



GENERAL DESCRIPTION. 



I have taken as a type for description the broad band of flags which 

 surrounds the oval of sericite-scliist in Goshen, upon which all the flagstone 

 quarries of this town are situated. The rock is a flat-fissile, arenaceous 

 muscovite-schist, splitting quite regularly into flags 2 to 3 inches thick and 

 of the largest size. It is of clear gray to rather dark-gray color, from a 

 constant content of graphite. It shows shining flat cleavage surfaces 

 pimpled with small garnets (co O). Staurolite, cyanite, and beds of lime- 

 stone are rare or wanting. 



' Geology of Vermont, Vol. I, 1861, p. 476. 

 MON XXIX 12 177 



