270 NEW YORK STATE MUSEUM 



eastern side, but have little importance elsewhere. The ophitic 

 limestones that have been quarried at different times belong to 

 the same series. The marbles of the Adirondacks comprise both 

 the calcite class, with very little magnesia, and the dolomite class, 

 containing high percentages of magnesia. No definite relation is 

 apparent in regard to the occurrence of the two and both may be 

 found in the same area in close association. 



The principal marble quarries in the Adirondack section are 

 found near Gouverneur, within the belt of Precambrian (Grenville) 

 limestones that extends from near Antwerp, Jefferson county, into 

 the town of Canton, St Lawrence county, having a length of some 

 40 miles and paralleled for much of the distance by the R. W. & 0. 

 branch of the New York Central railroad. In appearance it is a 

 medium textured stone of light gray or mottled gray and white, or 

 more seldom solid blue-gray color, that takes a lustrous polish. 

 It is adapted both for building and monumental work. On account 

 of its high carbonate content (95 per cent or more) it has been exten- 

 sively employed also for lime and furnace flux. There is normally 

 a small proportion of magnesium carbonate (6-7 per cent in most 

 examples) and occasionally this ingredient assumes the proportions 

 of a true dolomite, as instanced by the product of the White Crystal 

 Marble Co., north of Gouverneur. The main quarry section is 

 just southeast of Gouverneur, where the Gouverneur Marble Co., 

 the St Lawrence Quarries and other companies have engaged in 

 quarrying marble for building and montimental purposes. The stone 

 from this section is to be seen in many large structures in the principal 

 towns of New York and adjoining states. Marble has been quarried 

 at several localities near Canton, and also at Harrisville and Natural 

 Bridge, Lewis county. 



Serpentine is associated with some of the Grenville limestone of 

 the Adirondacks, producing such varieties as verd antique and 

 ophicalcite that are employed as ornamental stone. Verd antique 

 of handsome appearance has been quarried in the town of Pitcairn, 

 north of Harrisville; it occurs also near Keeseville, Essex county, 

 and at other places. Ophicalcite, mottled white and green m^arble, 

 occurs in the vicinity of Port Henry and near Minerva, Essex county; 

 small quantities have been employed for monumental and ornamental 

 work. 



The southeastern New York marbles occur in belts which follow 

 the north-south valleys, east of the Hudson river, from Manhattan 

 island, into Westchester, Dutchess and Columbia counties. They 

 are commonly white to light gray in color, well adapted for building 



