256 NEW YORK STATE MUSEUM 



turbed, and have a fine granular or occasionally microcrystalline 

 texture. Their outcrops can often be traced for long distances. 



The present discussions of the resources of limestone will be 

 restricted to an outline of the characters and distribution of those 

 representatives that have chief importance from an economic 

 standpoint. 



Ciystalline (mainly Precambrian) limestones. The Grenville 

 formation of the early Precambrian includes limestones among its 

 members, always metamorphosed and often surcharged with sec- 

 ondary silicates. Some occurrences, however, show a high content 

 of carbonates, ranking with the best of the nonmetamorphic lime- 

 stones, so that they deserve consideration in this place. They 

 appear in belts and isolated patches and are very unequally dis- 

 tributed within the Adirondack Precambrian region. The principal 

 development is in St Lawrence and Jefferson counties, where there 

 are four considerable belts, besides mmierous small exposures. The 

 argest area is the belt that stretches from Canton, St Lawrence 

 county, to near Antwerp village, Jefferson county, with a width of 

 from I to 7 or 8 miles and a surface of 175 square miles. A parallel 

 belt occurs a few miles northwest, about midway between the first 

 and the St Lawrence river, in the towns of Macomb, Hammond and 

 Rossie, St Lawrence county. Southwest of the main area is the 

 Edwards-Fowler belt, affording a very impure limestone in most 

 outcrops but occasionally fairly high in carbonates.' The fourth 

 belt lies farther southeast across the St Lawrence-Lewis county 

 boundary, and is well exposed near Harrisville, Bonaparte Lake and 

 Natural Bridge. In the interior of the Adirondacks the limestones 

 are rarely represented, although they are found in some of the valleys; 

 in Essex county 30 or 40 miles from the border, as around Newcomb 

 and Minerva, and with increasing frequency towards the Champlain 

 valley. On the north and south sides of the Adirondacks they are 

 sparsely developed. 



The Grenville lim.estones are quarried for marble around Gouver- 

 neur. Crushed stone, flux and lime are also made in this section. 

 The principal lime-burning operations have been carried on near 

 Richville and Natural Bridge; at the latter place the product is 

 magnesian lim.e, used for refractories and paper making. The 

 chemical character of the Grenville limestones is exhibited by the 

 following analyses : 



