REPORT OF THE DIRECTOR AND STATE GEOLOGIST 1903 113 



the Salina, and it would undoubtedly have been referred to this 

 formation at the time when the section was published, were it not 

 for the fact that Dr Clarke's idea of the geologic periods seems 

 to have agreed with that set for them by Mr Williams, namely, 

 that the geologic periods begin when the first fossils of that period 

 appear. 



The eastern limit of the known gypsum deposits is in Madison 

 county, though rocks of the Salina group are found as far east as 

 Schoharie. From Madison county to Buffalo more or less con- 

 tinuous deposits are to be found throughout the Salina depression. 

 Most of the deposits that have been developed have been found in 

 the hills rising above the level of the surrounding country, and as 

 a usual thing the gypsum deposit does not have a great thickness. 

 At Fayetteville the deposit reaches a thickness of 60 feet, and 

 between Syracuse and Marcellus several thousand tons were taken 

 out in making the railroad cuts on the Auburn division of the 

 New York Central Railroad. The thickness of the latter deposit 

 has not been measured, but from the outcrops that I have seen, I 

 should judge that it is from 40 to 60 feet thick. 



When the gypsum deposits of the State were first p*recipi- 

 tated, they were undoubtedly continuous, 'but glacial action and 

 the solvent action of Avater have taken away a great portion 

 of the gypsum, leaving isolated deposits under a slight covering 

 of rock or earth in a great part of the Salina depression. 



The gypsum deposits are pierced by all the salt wells in the 

 State outside of the Salina depression, but no information of 

 value is obtained from a study of the well sections. The salt 

 mines, however, give data that are very important. 



In the shaft of the Livonia salt mine,^ gypsum was found at a 

 depth of 1078 feet in Lower Helderberg rocks. The deposit is 9 

 feet thick and is a mixture of gypsum and a so called marlite. 

 At the depth of 1138 feet is another bed of gypsum 45 feet in 

 thickness, while at 1278 feet is an 18 foot deposit with a band of 



^Luther, D. D. Livonia Salt Shaft N. Y. State Mus. 47th An. Rep't. 

 1894. p. 215-324 ; N. Y. State Geol. 13th An. Rep't, p. 25-130. 



