8 NEW YORK STATE MUSEUM 



Outcrops of gypsum occur in the banks of both branches of Sawyers 

 creek, and the chff in the northern part of the village of Cayuga shows 

 the upper part of the bed and the overlying limestone. An old gyp- 

 sum pit, now nearly obliterated, situated between two drumlins 2 

 miles north of Cayuga and ^ mile east of the Mud Lock, seems to be 

 the most northern point at which gypsum has been quarried on this 

 quadrangle. 



The only fossil known to occur in the Camillus shale, and that 

 very rarely, is the ostracod Leperditia alta Conrad, though 

 obscure traillike markings sometimes seen may owe their origin to 

 another form of animal life. 



Bertie waterlime 



The gypsum beds are overlain by evenly bedded impure magnesian 

 limestone, medium hard and dark colored when freshly broken, but 

 weathering to a light bluish or yellowish gray on exposure and be- 

 coming softer. 



Faint deposition lines may be discerned throughout the formation 

 but the heavier layers which are i to 2 feet thick are usually quite 

 compact, breaking with a conchoidal fracture, while a few of the 

 others show quite distinct laminations and weather into a hard slaty 

 shale. Toward the west it becomes somewhat thicker and is less 

 homogeneous. In Erie county it is 49 feet thick and the upper part 

 is the cement rock from which a large quantity of natural or water- 

 lime cement is manufactured while the stratum next below is a dark 

 slaty rock. 



Waterlime cement was formerly made in the vicinity of Cayuga 

 Junction and near Auburn from outcrops of this rock, but none is 

 made now. 



Fossils are rare in this formation as exposed on the Auburn quad- 

 rangle, a few Lingulas of two species, an Orbiculoidea, a Rhyncho- 

 nella with Leperditia alta and fragments of eurypterids con- 

 stituting the fauna here, but in Erie county the cement rock has af- 

 forded a large number of remarkably fine specimens of eurypterids 

 and phyllocarids of the following species : 



Ceratiocaris acuminata Hall E. dekayi Hall 



Eurypterus lacustris Hall Dolichopterus macrocheirus Hall 



E. lacustris var. pachycheirus Hall Eusarcus scorpionis Grote & Pitt 



E. remipes De Kay Pterygotus buffaloensis Pohlman 



E. pustulosus Hall P. cobbi Hall \ 



