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mass of conglomerate boulders overlies a low ledge of the same 

 rock. The arenaceous beds are irregular, but seem to indicate 

 a low dip to the north. This conglomerate has been encoun- 

 tered under Mt. Vernon Street, in the tunnel for the Moon 

 Island sewer. 



On Warren Street, near Quincy Street, and on Washington 

 Street, near Codman Avenue and Townsend and Elmore 

 Streets, the conglomerate, though slightly undulating, will 

 average horizontal. This general absence of dip continues all 

 the way to Alpine Street, where the level layers of sandstone 

 stand out very distinctly ; but between James and Cliff 

 Streets the most northerly exposure on Washington Street 

 shows an apparent dip to the north of perhaps fifteen degrees. 



On this line and farther east the central band of approxi- 

 mately horizontal strata is nearly a mile wide, but along the 

 Boston and Providence Railroad it is narrower. In the vicinity 

 of the AVhispering Chimney, in the angle between Centre and 

 Highland Streets, the strata are about horizontal, showing 

 only a slight easterly dip. A large east-west dyke traverses 

 the north side of this ledge. On the hill above, near the Stand- 

 Pipe, the dip is unsettled, but begins to be northerly. On and 

 near the railroad, between Heath and Roxbury Stations, at the 

 large quarry already mentioned, on Tremont Street, nearly 

 one-fourth mile west of the railroad, and east of the railroad, 

 in the bold ledge at the western end of Linden Park, there is a 

 pronounced northerly dip of ten to twenty degrees. On War- 

 ren Street, near Walnut Street, in Brookline, the conglomerate 

 is canted slightly to the north ; and on the Woonsocket Division 

 of the New York and New England Railroad, nearly half a 

 mile east of Brighton Street, it dips north at an angle of 

 perhaps twenty-five degrees. West of this, along the north 

 side of the amygdaloid, all my observations show the same 

 general fact, a northerly dip not exceeding thirty or forty de- 

 grees, and diminishing rapidly toward the south. 



Taking a general view, I have observed that the conglomer- 

 ate not only becomes smaller-pebbled north and south from the 



