Luther — Geology of the Salt District. 



207 



The Lehigh shaft is twelve miles northwest, near Le Roy, and the 

 Livonia shaft about the same distance east from the Retsof mine. 



These shafts, as soon as the required depth was reached, were heavily 

 timbered and lined to prevent the falling of loose fragments of rock, leaving 

 only ten to twelve feet of that part of the salt bed in which the drifts and 

 adits of the mine are located, accessible for examination. 



The writer was present while the excavation of the Livonia salt shaft 

 was in progress, from May 1891 to August 1892, when the bottom of the 

 salt bed was reached at the depth of 1432 feet. Abundant opportunity was 

 afforded for studying the material brought out, and frequent visits to the 

 bottom of the mine were made for the purpose of determining the order of 

 succession, and obtaining correct measurements. 



The sinking of the Lehigh shaft at Le Roy, and of the Greigsville shaft 

 was in progress at the same time and several visits to each were made for 

 observation of any difference in the character and condition of the strata of 

 the same horizon at the three localities. (See report of State Geologist for 

 1893.) 



From information thus acquired and from that obtained from well records 

 and the statements of owners and operators of salt plants, it is believed that 

 the character and condition of the salt deposit is essentially the same 

 throughout the entire district, the only material difference being m the 

 thickness, and the number of intercalated layers of rock. 



At the close of the epoch in which the red shales were deposited, the 

 salt district of New York was covered by the wide shallow offshore borders 

 of a great interior continental sea, protected from strong currents and the 

 sudden ingress of large quantities of sea water ; the conditions required for 

 the crystallization of salt by solar evaporation existed, and the deposition of 

 the salt beds was begun. 



The crystals are very coarse and were formed in the mud, or embedded 

 in it by the action of the waves, as there is no regular stratification in this 

 part of the beds. 



A greater or less proportion of rock material, limestone, shale and 

 gypsum, is found in all of the lower bed, with which the salt crystals have 

 apparently been violently stirred up and mixed, the whole mass having a 

 coarsely granular or brecciated appearance. 



The crystals in this " mixed salt," as it is called by the miners, are 

 usually very clear and nearly transparent, though sometimes white and 

 opaque. 



