34 



SURFACE GEOLOGY. 



Shaw's mountain ; next east below the plateau ; southward from Fairlee 

 village and pond ; and at Ely station. In Orford it is wide north-west of 

 Soapstone mountain, and the river road runs upon it south to Jacob's 

 brook ; in the village it is the terrace at the east side of the street ; and 

 from near the mouth of Sawyer's brook it averages one half mile wide for 

 three miles south, leaving the river at the north line of Lyme, and extend- 

 ing along Clay brook nearly level to within one mile of Post pond. All 

 the modified drift above this regular terrace, embracing the plateau east 

 of Fairlee pond, the high terrace in Orford, which begins at the south foot 

 of Soapstone mountain, and the high remnants at each side of Jacob's 

 brook, must be referred to a common origin, being portions of an im- 

 mense deposit brought down in the Champlain period by Jacob's brook. 



This stream drains a large area west and north-west from Cuba and 

 Smart's mountains, flowing through Orfordville into the Connecticut by a 

 north-west course. An uncommon abundance of fine material was sup- 

 plied from the melting glacier over this area, and the northward flood 

 which transported it was turned up the valley by the vertical wall of 

 Morey's mountain. For a time the accumulation was too great to be 

 cleared away by the current of the main valley, which was filled by this 

 deposit north to Soapstone and Sawyer's mountains. A wide avenue was 

 next cut through this barrier by the Connecticut, which did not complete 

 till a later date the deposition of its own flood-plain, the remains of which 

 we have called its highest normal terrace. 



A few measurements of this remarkable tributary deposit will indicate 

 its extent and depth. It filled the valley for more than two miles north 

 from Orford, averaging a mile in width. The ordinary height of the river 

 here is 383 feet above the sea. The highest point of the plateau in Fair- 

 lee, a mile and a half north from the mouth of Jacob's brook, is S75 l 

 the lowest point where the current swept west across this plateau, one 

 third of a mile south of the former, is 532 ; on the east side, a mile and 

 a half north from the mouth of the brook, it is 530; and close at its 

 north side, 565. Along its course we also find a large amount of modi- 

 fied drift, rising in a mile and a half to 690, or more than 100 feet 

 above the comparatively level barrier which it had thrown across the 

 Connecticut valley. 



A peculiarly contorted band of clay (Fig. 6), in a layer of clayey sand, 



