PRIMITIVE LIMESTONE. 



229 



detected, as a single drop of acid will cause an ef- 

 fervescence. Its structure and appearance are too 

 well known to need description. It forms an ex- 

 tensive bed through the whole extent of Berkshire 

 county, and thence it stretches through Vermont far 

 north into Canada. The same range also extends 

 south through the State of Connecticut, where in 

 many places it is burned for lime. It also abounds 

 in New-Hampshire and Maine, and, indeed, in all 

 the states where the other primitive rocks are 

 found. Professor Hitchcock regards the Berkshire 

 deposite as one of the most extensive ranges of 

 primary limestone in the world. It is of a pure white 

 colour and of a highly crystalline texture, as may 

 be seen by examining the City Hall in the city of 

 New- York, which is built of this stone ; or the Gi- 

 rard College, Philadelphia. Blocks are obtained 

 from a ledge in Sheffield more than 50 feet long and 

 eight feet thick. We shall hereafter speak of the 

 economical uses of this valuable rock. 



The non-stratified or granitoid rocks, as they have 

 been called, contain, among others, the following 

 minerals, viz., iron, tin, zinc, plumbago (black lead), 

 titanium, molybdena, lead, copper, gold, beryl, gar- 

 net, topaz, tourmaline, zircon, chrysoberyl, pyrox- 

 ene, hyperstene, spinelie, epidote, pinite, idocrase, 

 diallage, &c. The same minerals are also found in 

 the stratified rocks ; and, in addition, anthracite coal 

 has been met with, though not in large quantities, 

 as at Worcester, Massachusetts, in mica slate.* 



* It is claimed by some geologists that this is a transition 

 formation. 



