p L A T v: ^^ I T 1 h. 



INCLUSION OF MUD IN UPPER SURFACE OF TRAP SHEET. 



. — A block of trnp from the contact of a sheet of samlstone 12 feet long and a foot wide which 

 was included in the trap a few feet below and parallel with the surface. The lower surface 

 of the specimen was in contact with the sandstone. The whitest Bpots are steam holes 

 filled by secondary calcite. V'he trap is full of drops and lobate masses of the gray mud. 

 From the north end of the east wall of the cut. Dibbles Crossing, Holyoke. AI>out two- 

 thirds natural .size. From photograph. See page 4.56. 



1. — Polished surfaces of pieces from the south end of the cut, to show the intimate mixture of the 

 shattered trap and the light-gray mud. The mud fills many of the steam holes in whole 

 or part. Natural size. From photograph. See page 456. 



428 



