8 



NEW YORK STATE MUSEUM 



side of the Seneca river for a mile east of Seneca Falls, and in 

 several places on the south side in cliffs and old quarries. More 

 than 5000 tons were quarried annually in this immediate vicinity in 

 the middle of the last century. 



This stratum is exposed in a line of quarries and natural outcrops 

 extending from Madison county to Genesee county showing a 

 variable proportion of gypsum in the clay shales at different 

 localities. 



The first discovery of gypsum in the United States is said to have 

 been made in the year 1792 at Camillus, N. Y. where the bed is 

 extensively exposed; hence the formation name. 



Traces of organic life are absent from the Camillus shale except 

 for the rare appearance of the little ostracod, Leperditia alta 

 (Conrad), and obscure markings that are perhaps trails made by 

 this or a similar organism. 



Bertie waterlime 



This is a mass of impure magnesian limestone, hard and dark 

 when freshly broken, but softening and changing to a light ashen 

 gray or buff color when exposed. 



It is usually in layers 3 inches to 10 inches in thickness, separated 

 by thin partings of carbonaceous matter. -Some of the layers are 

 quite compact and in these the rock has a conchoidal fracture; others 

 are thinly laminated and weather into a hard slaty shale. 



The " cement rock " so extensively quarried in Erie county is in 

 the upper part of this formation and some of the layers have been 

 burned and used as waterlime all along its line of outcrops in the 

 central and western part of the State. In this vicinity it has fallen 

 into disuse for that purpose, probably because it has been found 

 lacking in the proportion of silicon necessary to good cement. 



The Bertie waterlime is well exposed in the rock wall on the 

 south side of the river at Seneca Falls below the bridge and the 

 contact with the Camillus shale at the base may be seen in the 

 banks for half a mile eastward. As the upper contact is covered, 

 the thickness can only be estimated, but it is approximately 22 feet. 

 Fossils are rare in these beds but the few that do occur are exceed- 

 ingly interesting as the fauna is a peculiar association of crusta- 

 ceans, the remains of which while few and fragmentary in this 

 vicinity, are more common at Buffalo and in Herkimer county and 

 have made this horizon one of the most interesting of the New 

 York series. 



