THE HO USA TONIC VALLEY. 



799 



attains a greater thickness, no measurements could be made, 

 though it can safely be said that it does not exceed a few hun- 

 dred feet. The relations made out in the area now under consid- 

 eration, allow of a thickness which agrees well with that found in 

 Mt. Washington. A locality which illustrates this will be here 

 briefly mentioned, because the structure is so simple as to afford 

 reliable results. The locality is a knoll called Pine Hill, lying at 



Fig. 6. View of Pine Hill on the southeast flank of Tom's Hill, seen from a point 

 to the west. A, Riga Schist. B, Pine Hill composed of Egremont Limestone. C, 

 Approximate position of cap of Everett Schist. 



the southeast foot of Tom's Hill south of the railroad. The dips 

 are low, due entirely to pitch, and the thickness of the limestone 

 less than ioo feet. (This locality is marked P on the map). 

 North of the track (A in Fig. 6) is seen the Riga Schist pitching 

 south at an angle of about 3 5 ° . Across the track and a little farther 

 east is Pine Hill (B), composed of a pure, white limestone dipping 

 conformably over the schist, and capped on its south slope by a 

 thin layer of the Everett Schist. The outcrops of this rock are 

 hidden in the view, but their approximate position is shown by C. 

 The thickness of the Riga Schist and the Canaan Dolomite have 



