390 GEOLOGY OF OLD HAMPSHIRE COUNTY, MASS. 



with excavated hopper-shaped faces had been embedded in the mud, dis- 

 solved out, and their place taken by the calcite, which has largely impreg- 

 nated the sandstone, but which shows the white color only where it occupied 

 the cavities of the salt hoppers. 



The locality as given me by Mr. Diller is along the south bank of the 

 Westfield River, in West Springfield, near the water's edge, and just below 

 the large dam some distance above (west of) West Springfield ^^llage. 



Later a specimen was found at Holyoke, near the west end of the rail- 

 road bridge, and is now in the Smith College collection. It is larger and 

 much more delicate than the Westfield specimens. It is figured and described 

 in detail in the Mineral Lexicon.^ The piece must have come from a very 

 short distance northwest, and I have observed single hopper-shaped casts in 

 the shale at the cutting within the city of Holyoke, and similar forms on the 

 shale at Ashley's pond, farther west, and at many other localities in the 

 shale. In 1895 a large share of the finest specimens collected by Mr. Hos- 

 ford came into my possession — the best piece of all through the kindness of 

 his daughter. This is a finely ice-polished slab of black shale, covered with 

 small white figures, three or four to the square inch, in great variety, formed 

 by the A^arious cross-sections of single and aggregated cubes, whose faces 

 were excavated into hopper shapes to various depths. Three-rayed, four- 

 rayed, and six-rayed forms were most common. The center of each ray, 

 marking the trace of the six planes which connect the cube edges, is gener- 

 ally very dark, so that it stands out against the white calcite, and where the 

 faces are only slightly excavated, so that the calcite is now nearly a squai'e, 

 the resemblance to a chiastolite is striking. This darker band is calcite 

 colored by petroleum or coaly matter, and in some cases it is a quite wide 

 band of piu-e asphaltum. 



It would seem that the solution of the salt and its replacement by white 

 calcite progressed slowly from the outside at a low temperature. At the 

 last the central band of salt was removed and calcite took its place when 

 somewhat more elevated temperature prevailed, so that bituminous matters 

 were distilled into the empty spaces along with the last calcite. In other 

 specimens cubes are found with only slightly excavated faces, which are 

 made of quite coarsel}^ crystalline calcite, irregularly colored by bitumen. 

 Other pieces have slickensided faces, with surfaces of fine-fibrous graphite 



' Bull. U. S. Geol. Survey, No. 126, 1895, under "Salt." 



