QUARRY MATERIALS OF NEW YORK 20/ 



The Treadway quarry lies about a mile north of Port Henry on 

 the brook which flows into Lake Champlain at Craig harbor. The 

 opening shows lo to 15 feet of the limestone. 



Another quarry is north of the Cheever iron mine along the 

 highway on property now owned by the Cheever Iron Ore Co. Two 

 pits are to be seen on either side of the road, the one to the east 

 exposing 15 feet of rock which shows many streaks of serpentine. 



A quarry was once worked in the town of Thurman, Warren 

 county. According to G. P. Merrill ^ the stone contains about equal 

 parts of snow-white calcite and light yellowish-green serpentine in 

 particles from one-sixteenth to one-fourth of an inch diameter. 

 The texture is not very uniform. 



Serpentinous limestones are found in numerous other localities 

 in the Adirondack region, notably in the limestone areas in Essex, 

 Warren and St Lawrence counties. 



Serpentine unmixed with calcite is exposed over a large area on 

 Staten Island. The rock lacks the translucency and rich color 

 which are seen in the ornamental varieties, being usually dark 

 green to nearly black, and stained by iron oxides. It carries black 

 specks of chromite. The serpentine forms the central ridge of hills 

 from St George on the north to a little beyond Richmond. On the 

 borders the serpentine is mixed more or less with talc and tremolite, 

 but in the interior contains little of the silicates, although there may 

 be a few undecomposed remnants of pyroxene, olivine and amphibole 

 which are the parent minerals of the serpentine. Originally the 

 rock seems to have been a nonfeldspathic aggregate that most 

 resembles the basic igneous types of the pyroxenite-peridotite 

 group.- In most places it is badly fractured, being traversed by 

 narrowly spaced joints and showing more or less differential move- 

 ment along them, as a result probably of expansion of the mass in 

 the alteration. 



Serpentine also outcrops on Davenport's Neck at New Rochelle 

 and near Rye, Westchester county. 



An occurrence of serpentine in northern Essex county has been 

 the source of much handsome material for museums, but has not 

 been worked on a commercial scale. The serpentine occurs along 

 the sides of a ravine just west of Port Douglas on the road to 

 Keeseville. It is found only within the ravine, as above it is con- 



1 Op. cit. p. 66. 



2 The derivation of the serpentine is discussed by the writer in School 

 of Mines Quarterly, v. 22, 1901. 



