MINERAL KESOURCES OE tHE STAtE OF NEW YORK 



259 



Upper Cambrian limestones. These are mostly magnesian lime- 

 stones and dolomites that were earlier classed as^Calciferous, but 

 now given independent places in the classification. They include 

 the Hoyt limestone, which is exposed in the vicinity of Saratoga 

 Springs, and the Little Falls dolomite as the main members, both 

 rather impure massively bedded rocks that find use mainly for 

 foundation work or crushed stone. They are dark gray, weathering 

 to buff, with a proportion of lighter grains or rhombs of calcite which 

 give an irregular subcrystalline texture to the materials. The Little 

 Falls dolomite is well shown in the old quarries about Little Falls 

 and east of there at St Johnsville, Canajoharie and Cranesville in 

 the Mohawk valley. The general composition of the rock is indi- 

 cated by the analyses below of samples from Little Falls (i) and 

 from Amsterdam (2) quoted from Bulletin 44 of the New York 

 State Museum: 





Analyses of Cambrian limestones 







I 



2 



SiOa 



10.5 

 303 



■77 

 47.96 

 36.89 



7.46 



2.48 



1 .07 



18.19 



71.76 



AI2O3 



FeoOs 



MgCOs 



CaCOg - - - 







Ordovician limestones. In the succession of Ordovician strata 

 limestones are represented in force in the Beekmantown, Chazy, 

 Lowville, Black River and Trenton formations. They are distrib- 

 uted over quite an extensive surface, mainly on the eastern, southern 

 and western borders of the Adirondacks. 



The Beekmantown limestone, now limited to the middle and 

 upper beds of that series as formerly defined, is developed in the 

 Champlain valley. It occurs on the New York side in detached 

 areas, usually down-faulted blocks that are remmants of a once 

 continuous belt. It is represented in the basal portion of the lime- 

 stone area that outcrops in Washington, Saratoga and Montgomery 

 counties along the Adirondack margin. In the Champlain valley it 

 has been quarried at Port Henry for furnace flux for local use. 

 Quarries have been worked near Amsterdam, while at Tribes Hill 

 occurs an earlier but quite similar stone, called the Tribes Hill 

 limestone, that has also been worked. 



