GYPSUM DEPOSITS OF NEW YORK 6l 



The impurities of the rock are such as mig-ht be expected from 

 the stratigraphic associations. The principal foreign ingredients 

 are lime and magnesia carbonates, clay and quartz. The iron shown 

 by the analyses is mostly present probably in the clay. The high 

 percentage of magnesia in the rock of the eastern section is a 

 striking feature, since it appears to be greatly in excess of the pro- 

 portions found in dolomites. The presence of free carbonate is 

 thus indicated. 



PERMANENCE OF THE GYPSUM SUPPLY 



There are no sufficient data on which to base an estimate of the 

 available gypsum supply, but in view of the magnitude of the 

 known deposits it would be a gratuitous task to attempt any formal 

 calculation. The production of 4,000,000 or 5,000,000 tons in the 

 past is insignificant as compared with the amount that still lies on 

 the surface. It represents an equivalent of 40 or 50 acres of the 

 thickest beds, such as are foimd in Onondaga and Cayuga counties, 

 or about 400 acres of one of the 4-foot beds in the western section. 

 The existing mines and quarries could maintain the present rate 

 of production of 350,000 tons a year for an indefinite time. The 

 extension of the workings in depth or the opening of additional 

 areas on the outcrop will bring new supplies, as they are needed, 

 into the zone of exploitation. 



METHODS OF PROSPECTING AND EXPLOITING THE GYPSUM 



DEPOSITS 



There are certain facts and inferences bearing upon the distri- 

 bution of gypsum in the New York Salina beds that may be found 

 useful in the conduct of exploratory work. 



The main deposits occur in the upper Saiina shales, and there- 

 fore their horizon of outcrop is near the southern border of the 

 belt as traced on the map. Little is known of the character of the 

 gypsum which belongs to tlie salt-bearing shales proper, and if rep- 

 resented anywhere in the present Avorkings its identity has not been 

 established.^ The pockets of impure gypsum that are described 

 from the eastern section of the belt quite likely occur at different 

 horizons, since they are probably due to solution and rodoi>csition 

 of the gypsum rock, Inil they have little industrial innportance. 



1 Tne deposits once worked at Port Gibson. Ontario co. seem to lie at a 

 lower horizon than the other occurrences in the State and may be below the 

 Camillus shale. The present investij^ation. however, did not uncover any 

 definite evidence of their association "with^the rock salt series. 



