GEOLOGY OF THE CONNECTICUT VALLEY DISTRICT. 407 



covered up the first formed hummocks. Still later, the force elevating 

 the calcareous schists showed itself; and, perhaps in conjunction with it, 

 came the outburst of sienite constituting the principal mass of the two 

 mountains. This was the proper epoch of the eruption of this mountain 

 mass. In this respect it agrees with the supposed age of such mountains 

 as Pequawket, and perhaps the whole series of elevations composed of 

 Chocorua granite. 



In the Geology of Vermont {vol. i, p. 225) my father presents the theory 

 that the adjacent mica schists must once have existed upon both sides of 

 the erupted mass of Mt. Ascutney, at least to equal it in height. If the 

 sienite were once in a melted condition, it would require walls of schis- 

 tose rock to keep it in place, and thus prevent its flowage over the sur- 

 rounding county. He presented this theory in order to illustrate the fact 

 of enormous erosions by atmospheric agents along the Connecticut val- 

 ley. Other authors would not say this granitic rock had been melted, 

 like lava, but that it was formed under a pressure equal to ten thousand 

 or twelve thousand feet of strata. According to either view, the argu- 

 ment for an enormous amount of erosion would hold good. 



We have been unable as yet to prepare our usual "specimen map" of 

 this second section of the Connecticut valley, together with a catalogue 

 of the rocks obtained for the museum, upon which our descriptions are 

 based. Should the map and catalogue be presented, they will be found, 

 with the corresponding descriptions of the two southern sections of the 

 Connecticut valley, at the close of this chapter. 



