Range and Extent of Granite. 



469 



Topography of Granite. 



Probably there is not a town in Massachusetts in which more or 

 less of granite does not occur, either in situ, or as bowlders. And no 

 rock is probably so generally known as this : though the term is often 

 very loosely applied. 



To begin with the eastern part of the State : It will be seen by the 

 map that granite lies between the sienite on one side, and mica 

 slate and gneiss on the other, nearly across the State ; from Andover 

 to R. Island. Generally this granite is coarse, and it forms no hills 

 of much altitude. Obviously it has been powerfully abraded by cur- 

 rents of water. In elevation it is intermediate between the greenstone 

 on one side, and the gneiss on the other; that is, as we pass from the 

 coast westward, we gradually ascend '; rising slightly from the alluvi- 

 um to the graywacke ; still more as we come upon the greenstone and 

 the sienite ; still more to reach the granite, and still more in the re- 

 gion of gneiss. The height of land between the ocean and Connect- 

 icut river, is not attained till we pass west of the valley of Worcester. 

 A glance at the sections accompanying this Report will render these 

 statements obvious. (Plates XVII and XVIII.) 



The southern part of the range of granite above spoken of, is fine 

 grained and passes into sienite, especially in Rhode Island. In the 

 vicinity of Providence it is extensively wrought for architectural pur- 

 poses. The splendid columns of fine grained white granite in the 

 Arcade in that city, were obtained from a quarry in Johnstone, 5 

 miles northwest of Providence. " They are twelve in number," says 

 Dr. Webb, "cut out of solid blocks, 21 feet long, 3 feet in diameter at 

 the base, and w r eigh 11 tons each. It required 11 yoke of oxen to 

 draw each one into town. It is calculated that it would have taken 

 one man upwards of six months, to have wrought one of these col- 

 umns. The stone for the first five locks of the Providence and Wor- 

 cester canal, was also obtained from this quarry." 



The broad deposit of granite marked between Narraganset and 

 Buzzard Bays, consists chiefly of the common varieties. Much of it 

 is extremely coarse. But in some places, as at Fall River in Troy, 

 the grain is fine and the rock well adapted to architecture. Along 

 the western border of this range the rock appears in place in great 

 abundance ; but as we pass easterly, the surface is almost entirely 

 covered with bowlder stones, mostly of granite. On its northern 

 margin, however, where we approach the graywacke, the loose blocks 



