362 rocks. 



and there are numerous others in the Connecticut valley, 

 both in Connecticut and Massachusetts. A variety in North 

 Haven, at the east end of Mount Carmel, has been spoken 

 of as excellent for ornamental architecture. That of Long- 

 meadow and Wilbraham, in Massachusetts, is a very fine 

 and beautiful variety and is much used. A freestone occurs 

 also at the mouth of Seneca creek, Maryland, convenient for 

 transportation by the Chesapeake and Ohio canal ; white 

 and colored sandstones occur also at Sugarloaf mountain, 

 Maryland. 



The sandstone of the Capitol at Washington, is from the 

 Potomac ; it is a poor material. 



Sandstones when splitting into thin layers, form excellent 

 flagging stones, and are in common use. 



Hard, gritty sandstones and the grit rocks are used for the 

 hearths of furnaces, on account of their resistance to heat. 

 They are also much used for millstones, and when of firm 

 texture, make a good substitute for the buhrstone. 



The true buhrstone has been described as a cellular 

 siliceous rock, without an apparent granular texture. The 

 buhrstone of Ohio approaches this character ; it is in part 

 a true sandstone containing fossils in some places, and over- 

 lying the coal. Much of it contains lime ; and it is possible 

 that the removal of the lime by solution, since its deposition, 

 may have occasioned its cellular character. It has an open 

 cellular structure where quarried for millstones. It occurs 

 in Ohio, in the county of Muskingum, and the counties south 

 and west of south, on the Raccoon river and elsewhere. 

 The manufacture commenced in this region in 1807, and u> 

 Richland, Elk, and Clinton, and in Hopewell, the manufac- 

 ture is now carried on extensively. Stones 4 feet in diame- 

 ter bring $150.* 



The " green sand" of the cretaceous ibrmation contains 

 grains of silicate of iron and potash, to which it owes its 

 greenish tint. It occurs abundantly in New Jersey as a soft 

 rock, and is much used for improving lands : a value it owes 

 mostly to the alkali it contains. 



Pudding stones and breccias are fitted, in general, only for 

 the coarser uses of stone, as for foundations, butments of 

 bridges. Occasionally when of limestone, they make hand- 

 some marbles, as the "Potomac breccia marble" on the 



• S. P. Hildreth, Geol. Report, Ohio. 



