426 NEW YOKE STATE MOSEUM 



magnesian limestone. Nearly all of the limestones, which are 

 quarried for building stone, in Orange and Dutchess counties are 

 from this formation. The stone occurs generally in thick and 

 regular beds. It is hard, strong and durable and is adapted for 

 heavy masonry as well as for fine cut work. The quarries near 

 Warwick, Mapes' Corners and near Newburgh in Orange county 

 and those on the Hudson River, near New Hamburg, are in the 

 Calciferous. The Sandy Hill quarry and those at Canajoharie 

 and Little Falls are also in it. 



Trenton Limestone. 



Under this head the Chazy, Birdseye, Black River and Trenton 

 limestones are included. 



The Chazy limestone crops out in Essex and Clinton counties 

 and in the Champlain valley — its typical localities. The beds 

 are thick and generally uneven. Regular systems of joints help 

 the quarrymen in getting out large blocks. Quarries at Wills- 

 boro Point and near Plattsburg are in the horizon of the 

 Chazy. The stone is suitable for bridge work and for heavy 

 masonry. 



The members of the Trenton above the Chazy limestone are 

 recognized in many outcrops in the southeastern part of the 

 State; in the Hudson-Champlain valley; in the Mohawk val- 

 ley ; in the valley of the Black River and northwest, border- 

 ing Lake Ontario ; and in a border zone on the north of 

 the Adirondacks, in the St. Lawrence valley. In a formation 

 so widely-extended there is, as might be expected, some 

 variation in bedding, texture and color. Much of the 

 Trenton limestone formation proper is thin-bedded and shaly 

 and unfit for building stone. In the Birdseye also the 

 stone of many localities is disfigured on weathering, by its pe- 

 culiar fossils. Generally the stone is sub-crystalline, hard 

 and compact and of a high specific gravity and dark- blue 

 to gray in color. But the variation is wide, as for example , 

 between the black marble of Glens Falls and the gray, crystalline 

 rock of the Prospect quarries near Trentun Falls. The variation 

 is often great within the range of a comparatively few feet ver- 

 tically ; and the same quarry may yield two or more varieties of 

 building stone. In several quarries the Birdseye and Trenton 



