BUKR: MELAPHYR OF BROOKLINE, BRIGHTON, AND NEWTON. 59 



Figure 2). - The cutting and distorting of the bedding planes is strik- 

 ingly shown. 



The third exposure is intermediate between, but considerably south 

 of, the other two. The melaphyr mass is here not more than fifteen feet 

 thick, and is bordered by slate on both sides. The slate on the northern 

 or upper side lies in patches on the melaphyr. Here, again, a zone of 

 baking is developed along the contact, while the cutting of the slate 

 by the melaphyr is quite as conspicuous as it is in the other two 

 localities. 



The two melaphyr bodies occurring next to the north make up a sin- 

 gle ridge, or rather a succession of melaphyr knobs. Slate appears in a 

 number of places on these knobs. These patches of slate are connected, 

 on Mr. "Woodward's map, to form a parting between the two supposed 

 flows. A narrow, wedge-shaped mass of slate occurs at Locality 26 

 (Plate 2), west of Webster Street. The melaphyr just below this slate 

 contains fragments of it. On the contact, the influence of the igneous 

 mass is apparent. The slate is broken by very many small faults. These 

 do not pass into the melaphyr, the line of contact between the slate and 

 the igneous rock being quite continuous. It is probable that these faults 

 were produced by disturbance attendant upon the intrusion of the igneous 

 rock, the effect being obliterated along the contact by the influence of 

 the molten mass. A second exposure of slate occurs on this line on the 

 west side of Webster Place. The evidence here is not so striking, but is 

 quite as good as in the other places. A third locality appears, on Wood- 

 ward's map, on Cambridge Street, behind the Couvent (Plate 2, Loc. 18). 

 This outcrop shows, in the most conclusive manner, the extremely com- 

 plicated way in which the melaphyr has been forced into the sediments. 

 In fact, the whole outcrop is practically a breccia of great slate and sand- 

 stone blocks, held in a matrix of melaphyr, which fills all the cracks and 

 penetrates the sediment in thousands of tongues. The sandstone blocks 

 themselves are shattered so that they have the appearance of a fault 

 breccia and these small displacements do not pass across the contact into 

 the igneous rock. 



Another portion of this mass is shown in contact with slate and sand- 

 stone on Cambridge Street, opposite Saunders Street (Plate 2, Loc. 17). 

 Recent blasting at this point makes it possible to obtain very fine hand 

 specimens, showing the intricate way in which the melaphyr has pene- 

 trated the sediment. The fifth and sixth " flows " do not appear in con- 

 tact with overlying sediments. 



No other contact exposures are known, excepting several in the Allston 



