432 STRATIGRAPHICAL GEOLOGY. 



the position of the strata is essentially the same, while the hornblende has 

 diminished in amount, occurring in two places. This rock occurs about a 

 mile south of the Vernon line, along Bennet's brook, dipping south-east- 

 erly. My father's map of Massachusetts represents this hornblende band 

 as extending along the east line of Bernardston southerly, reaching to the 

 Connecticut river at the ferry leading to Northfield village, thence occu- 

 pying the whole area from the Connecticut west to Woodard's or Una- 

 dilla brook. My own observations confirm and extend this area, at the 

 expense of the red sandstone. Less than a mile from the Turner's Falls 

 ferry, in Gill, the hornblende rock shows itself; and I did not see any- 

 thing else as far as to the ferry crossing to Northfield, where are also 

 some related metamorphic strata. I also find this rock over a mile to 

 the south-west from Grass hill, dipping somewhat south of east. Be- 

 tween this point (four corners in the road) and Otter pond, in the north- 

 west corner of Gill, are extensive quartz ledges, with north-westerly dip. 

 We may therefore extend the hornblende more south-westerly than be- 

 fore, and perceive its want of conformity to the quartzite, on account of 

 the change in the dip. The north part of Gill is covered with the irreg- 

 ular lenticular hills of drift, to be described hereafter. Without doubt 

 their abundance has led previous observers to overlook the presence of 

 the older schists, and to believe the place occupied by the Trias. Our 

 sketch shows that the hornblende pursues a more north-easterly course 

 than is indicated upon the Massachusetts geological map. 



3. Cambrian Slates. 



Clay slates occupy the western part of our map. It is believed to be 

 the same band with that described in the second section of Connecticut 

 river, between Hartland and Fairlee. The range commenced again in 

 Rockingham, and is continuous thence to Brattleboro', Guilford, and 

 Bernardston, terminating in the north part of Greenfield, because covered 

 by the Trias. The last remnant of it to the south is represented upon my 

 father's map as situated in Whately. There are quarries of slate upon 

 this range in Dummerston and Guilford. 



Observ^ers have not been agreed as to the age of this band. My father's 

 latest views led him to suppose these slates identical with those over- 

 lying the fossiliferous limestone at Mr. Williams's house in Bernardston ; 



