THE LEYDEN ARGILLITE. 205 



The Leyden argillite, as it runs north tlu-ough VeiTQont, borders aTid 

 eveiy where rests upon the Conway schist, where tliey are not verticah' In 

 the discussion of the argillite in the Vermont survey it is placed, without 

 hesitation, above the schist; indeed, is still associated with the limestone and 

 assigned to the Devonian.^ In the Geology of New Hampshire, Professor 

 Hitchcock has shown that the "calciferous mica-schist" dips beneath the 

 argillite clear across the State. 



The much more pronounced metamorphism of the schists, the abun- 

 dance of great granite veins containing rare minerals, as well as the long 

 series of minerals found in the schists themselves, may be contrasted with 

 the barrenness and low degree of metamorphism of the argillite as indicat- 

 ing that the schist is the older rock. The microscopic description of the 

 two rocks may be compai-ed from this point of view. 



The locality at the brook west of Whately -snllage (see page 196) is 

 also a decisive one in reference to the question of the relations of the two 

 rocks under consideration. That the triangular area of argillite occurring 

 here is a continuation of that in the Beniardston area is quite certain, in 

 view of their complete identity, and has not been doubted by anyone ; and 

 that the black limestone, with its border of hornblende rock, is the common 

 limestone of the lower fonnation is equally clear; but the latter is here 

 thrust up through the argillite in a knob, like a button through a button- 

 hole, and the argillite mantles around it and dips away from it on all sides, 

 and this is far out in the middle of the argillite, showing that the latter is 

 underlain by the Conway mica-schist, which dips under it on the west. The 

 relations of the two are indicated upon the sketch map (fig. 11, p. 197). 

 A few rods farther south, and on the opposite side of the road, the limestone 

 again buckles up twice through the argillite. 



CONTACT METAMORPHISM OF THE LEYDEN ARGILLITE BOEDERING THE 

 TONALITE CI-' HATFIELD. 



A band about 1,300 feet wide, bordering the tonalite on the west, 

 commencing in the woods west of the school south of Whately village 

 and extending southwest across Hatfield to its southwest comer, shows on 

 the exact contact a nan'ow band of green seiicite-gneiss, and outside this a 



' Geology of Vermont, Vol. II, 1861, Pis. XV and XVI. 

 nbid., p. 497. 



