224 ITNSTRATIFIED 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, 
