BURR: MELAPHYR OF BROOKLINE, BRIGHTON, AND NEWTON. 63 



For a mile west of the reservoir the slate seems to be quite lacking. It 

 next occurs in a limited exposure on Beacon Street, a half-mile east of 

 Newton Centre (Plate 2, Loc. 20). Here again there is strong evi- 



Figurk 1. Section A A'. 



dence of overthrusting. The conglomerate cuts diagonally across the 

 slate beds, and its under surface is deeply scored in the direction of the 

 thrust. The relations here differ from those at Chestnut Hill. The 

 slate dips north at a very low angle, while the overlying conglomerate 

 has a much steeper dip (Figure 2). This relation is not suggestive of 

 synclinal structure in the slate. If a syncliue was developed in the 

 eastward extension, it is safe to say that it did not extend to this point. 

 Farther west the. slate belt, if it exists, is covered beneath the glacial 



Figure 2. Section B B'. 



deposits of Newton. It seems extremely probable that it does underlie 

 a portion of the low laud extending along the line of Beacon Street. It 

 appears again on the east side of the Charles River. Outcrops of slate 

 and conglomerate occur near Chestnut Street, north of Newton Upper 

 Falls, and a considerable outcrop of slate has recently been exposed east 

 of Newton Lower Falls, near Waban Avenue (Plate 2, Loc. 23). In 

 all exposures the slate is contorted and crushed, indicating that it has 

 undergone something of the strains experienced by the rocks farther 

 toward the east. At Newton Lower Falls a ditch has disclosed fine 



Figure 3. Section C C 



conglomerate (Fig. 3), such as is frequently found immediately beneath 

 the slates. This seems to indicate that the fault was dying out toward 

 the west, the throw not being sufficient to bring up the lower members 

 of the conglomerate series. It is evident that the fault fades out in like 



