16 



Economical Geology. 



of this granite to water transportation, will always render it pecul- 

 iarly valuable. 



The granite range extending from Cohasset and Gluiney, through 

 Randolph, Stoughton, Foxborough, &c. into Rhode Island, with one 

 interruption by graywacke, affords much valuable stone for architect- 

 ural purposes ; and it is wrought more or less in every town through 

 Avhich it passes. About two and a half miles to the west of Provi- 

 dence, (R. I.) it is quarried; and thence were obtained the beautiful 

 and magnificent pillars in front of the Arcade in that place- 

 That part of this extensive deposit of granite, which is fully devel- 

 oped a little south-west of Dedham, furinshes some beautiful varieties 

 of stone. No better example can be referred to, than the elegant pil- 

 lars of the Court House in Dedham. This granite is very fine 

 grained, and so white, that at a short distance it cannot be distinguished 

 from white marble. The pillars just named were obtained from some 

 large bowlders near the dividing line between Dover and Medfield. 



The stone used in Boston, under the name of Chelmsford granite, 

 is found in a range of this rock, not connected with the deposit that 

 has been described above. Nor does it come from Chelmsford ; but 

 from Westford and Tyngsborough. In the latter place, it is obtained 

 chiefly from bowlder stones ; but ledges are quarried in Westford. I 

 do not know why it has been called Chelmsford granite, unless from 

 the fact that large quantities are carried to Lowell, (formerly a part 

 of Chelmsford,) to be wrought. This rock is pure granite, with no 

 hornblende ; and being homogeneous and compact in its texture, it 

 furnishes an elegant stone. Good examples of it may be seen in the 

 pillars of the United States Bank, and in the Market House in Bos- 

 ton. These were from Westford. 



Four miles north of Lowell, a quarry of this granite has been 

 opened, in Pelham, (N. H.) Blocks may be obtained from this place 

 of any length under thirty feet. It is a very fine variety, is much 

 Used, and appears superior to the Chelmsford granite. 



The Westford and Pelham granite is connected with an imperfect 

 kind of mica slate, in which it seems to form beds, or large protruding 

 masses. In the same mica slate at Fitchburg, a little south of the 

 tillage, is a large hill of the same kind of granite. This is quarried 

 though not extensively, on account of the little demand for the stone. 

 This single hill, 300 feet high, and nearly a mile in circumference at 

 its base, might furnish enough to supply the whole State for centuries. 

 Some of it, however, is too coarse for architecture. 



