147 



gneiss with a steep north-east dip, which appears to be the 

 lower portion of the Montalban brought up by a fault. Be- 

 yond this, just west of Wads worth's Station, and a little 

 farther east than represented on the map, we cross the Huronian 

 border. The contact is not seen, here, but farther south, in 

 West Wrentham, the " metamorphic slate " belt swings to the 

 east and meets the Huronian granite, which is clearly eruptive 

 through it, showing that these altered rocks, although dipping 

 toward the Huronian, undoubtedly belong to a newer system. 

 There is evidence of extensive vertical movements all along 

 this part of the Huronian boundary. 



According to Hitchcock and Jackson the belt of altered 

 rocks is traceable southerly as far as Providence, Rhode Island, 

 or beyond, though the conglomerate character, to which it owes 

 its chief interest here, is less pronounced in that direction ; and 

 the micaceous, chloritic, and quartzitic beds in Smithfield and 

 Cumberland, mentioned on p. 128, which clearly underlie this 

 belt, may, with much probability, be connected with the mica 

 slate, etc., of Blackstone. Toward the north the rocks in ques- 

 tion cannot be followed much if any beyond the northern line 

 of Bellingham, giving way to gneiss in that direction. 



The so-called "metamorphic slate" of Bellingham, which 

 we have now located stratigraphically, begins on the west as a 

 well-marked hydro-mica slate, alternating repeatedly with beds 

 of sandstone and conglomerate, which are also more or less 

 micaceous, the sandstone and smaller-grained conglomerate, 

 especially, being, on this account, often with difficulty recog- 

 nized as such. The best exposure of this part of the series 

 which I have seen is in a cut on the New York and New Eng- 

 land Railroad (main line) a short distance east of Mill River 

 and near the eastern boundary of Blackstone. Farther east 

 the formation appears to undergo a gradual change toward 

 argillite, becoming at once less micaceous and less conglomer- 

 ate ; and the highest beds observed are a very good argillite, 

 though still slightly micaceous. 



The facts seem to warrant the correlation of these argilla- 



