BURR : MELAPHYR OF BROOKLINE, BRIGHTON, AND NEWTON. 65 



Albany Railroad, east of Auburndale. The dip is here 40° toward the 

 south. As this is discordant with the dips in all neighboring exposures, 

 it is evident that some irregularity of structure, probably a fault, has 

 brought the conglomerate to the surface at this point. The scarcity of 

 outcrop in this area is, in itself, nearly sufficient evidence of the small 

 importance of the conglomerate, for this is a resistant rock and has a 

 way of asserting itself wherever it occurs. It does not seem necessary 

 to regard these limited exposures of conglomerate as the equivalent of 

 the thick beds to the south of the melaphyr. 



The series, reading from south to north, is made up of conglomerate, 

 growing finer northward, interbedded sandstone and conglomerate, sand- 

 stone, and slate associated with melaphyr, slate with interbedded con- 

 glomerate, and finally a broad area of slate stretching away to the 

 crystallines on the north. This section does not yield evidence of a 

 repetition such as would be demanded on the supposition of an anti- 

 clinal fold. 



There are no details of structure which indicate anticlinal folding 

 about the melaphyr or synclinal about the slate. Folded strata are un- 

 known in the region, if we except some crumpled slates on the line of the 

 great fault. There is no changing of strikes at the eastern end of the 

 northern belt of conglomerate, nor about the western end of the inter- 

 vening slate belt. On Cedar Street, at the western end of the supposed 

 syncline, the conglomerate maintains its generally east and west strike 

 up to its last outcrop, within fifty feet of the melaphyr to the west. 



The conclusion as to the structure is that the conglomerate of the 

 southern area is anticlinal, and dips conformably beneath the slate of 

 Chestnut Hill and Newton Centre, while the northern area is brought 

 to the surface by a fault on which it has been thrust over the slate and 

 tilted toward the north. The lower members of the conglomerate series 

 would occur in the centre of the Brookline area and on the southern 

 edge of the northern belt. In these places, therefore, the melaphyr 

 would be expected to occur if it were associated with the basal rocks. 



It has been stated that melaphyr does occur in the axis of the Brook- 

 line anticlinal area. No melaphyr is seen, however, on the southern 

 edge of the northern area. The long arm which extends eastward from 

 Newton Lower Falls is associated with rocks which are considerably 

 above the base. The two areas of Newton Upper Falls and Newton 

 Centre are south of the slate belt and therefore not associated with the 

 northern conglomerate area. It is conceivable and even probable that 

 the throw of the fault has not been sufficient to disclose the lowest beds 



