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(likes, the eonolomerute series of Njintasket and Hingham, 

 iuchiding tlie conglomerate proper and the red and green sand- 

 stones and shales, bears a marked reseml)lance to the undoubted 

 Carboniferous strata of the Norfolk Basin, extending from 

 Braintree south of the Blue Hills to Wrenthani, where it joins 

 the Narragansett Basin. The conglomerate series of the 

 Norfolk and Narragansett Basins underlies the true Coal 

 IVIeasures, and has been referred with nuich probability to the 

 horizon of the Millstone Grit. Now, since it is the nature of 

 volcanic phenomena to be localized, there appears to be no 

 serious obstacle in the way of referring the conglomerate series 

 of the Boston Basin, with the associated igneous rocks, to the 

 same horizon ; and we may reasonably suppose that, in conse- 

 quence of the more yielding nature of the crust indicated by the 

 igneous phenomena, while the formation of the conglomerate 

 series was followed in the southern basins by conditions favorable 

 to the formation of beds of coal and the enclosing shales and 

 sandstones, a marked local depression made the site of the 

 Boston Basin a deep-water area over which were deposited 

 the barren slates which now overlie the conglomerate series. 

 It is desired to simply suggest this correlation here, and the 

 various facts which support it will be more fully set forth in 

 Part III. 



