224 



TJNSTRATIFIED ROCKS. 



of its boundaries. We shall, therefore, only pre- 

 sent a few brief notices of its occurrence. A belt 

 of granite traverses nearly the whole breadth of 

 Massachusetts. Commencing near Andover, it runs 

 between a region of syenite on the east, into which 

 it sometimes graduates, and a belt of gneiss and 

 mica slate on its west, as far south as Rhode Island. 

 Portions of this mass, especially in Rhode Island, 

 are fine-grained, and well adapted for architectural 

 purposes, for which it is extensively wrought in the 

 vicinity of Providence. Another broad mass of this 

 rock extends from the coast of Narragansett and 

 Buzzard's Bays, in a northeast direction, towards 

 the opposite side of the Peninsula of Massachusetts. 

 This, though usually coarse-grained, is in some pla- 

 ces, as at Fall River, of a fine grain, and suitable for 

 building. As we go farther west we meet with de- 

 tached masses of granite protruding through the 

 gneiss and mica slate ; and a similar arrangement 

 prevails in the districts of New-England to the north 

 of this state. For example, wide expanses of gran- 

 ite rocks show themselves near the coast, and as 

 we proceed westward they become merely isola- 

 ted masses, as it were, thrust through the gneiss, 

 mica slate, and other stratified rocks. Granite of 

 very superior beauty, associated with syenite, ex- 

 tends in a convenient belt around Boston, at a dis- 

 tance of 10 or 20 miles, upon the north, west, and 

 south. From Cohasset to Quincy, and also between 

 Cape Ann and Salem, it is very extensively quar- 

 ried, the rock from the large quarries being now 

 widely known in many of the cities of the United 

 States. At the quarry at Fall River, blocks of beau- 

 tiful granite, from 50 to 60 feet long, are sometimes 

 procured. At the quarries in Quincy have lately 

 been obtained eighteen pillars for the New- York 

 Exchange, being the largest ever procured in this 

 country, weighing each 33 tons. They are fluted, 



