GEOLOGY OF THE GENEVA-OVID QUADRANGLES 



27 



r e 1 1 a and containing many other species not found below that 

 horizon. This calcareous band formerly known as the Styliola lime- 

 stone was designated Genunclewa limestone in New York State 

 Museum bulletin 63, from its favorable exposure at Genundewa 

 point on Canandaigua lake. The layers of limestone do not appear 

 on these quadrangles, their most eastern exposure being in a small 

 ravine 2^2 miles south of the village of Gorham, Ontario co. 

 but in their place a distinctly marked band of soft gray calcareous 

 and fossiliferous shale is found that has at its base a row of large 

 flattish concretions which in the cliffs south of Big Stream point on 

 Seneca lake and a few other localities form a continuous layer of 

 rather soft concretionary limestone. 



The formation emerges from the lake at Starkey point on the 

 west side and Faucetts point on the east and is displayed in the cliffs 

 toward the north with fallen concretions and blocks of the gray 

 shale strewn along the beach beneath. It may be seen in the walls 

 of Lodi glen and other ravines, and is accessible in the Lehigh 

 Valley Railroad cut at Willard. It is covered by drift in the eastern 

 part of the quadrangle. 



An anticlinal fold brings the concretionary limestone above the 

 water south of Big Stream point (Glenora) 2^ miles south of 

 these quadrangles. This is the locality referred to by Professor 

 Hall on page 214 of the Report of the Fourth Geological District 

 under an erroneous impression that it was Tully limestone. 



This formation was described by Dr D. F. Lincoln on pages 99 

 and 100 of the Fourteenth Annual Report of the New York State 

 Geologist and correlated as the base of the Portage group. The 

 fossils collected by him from this gray band on Seneca lake were 

 identified by Dr Clarke as follows : 



Manticoceras patersoni (Hall) 

 Bactrites sp. 



Gomphoceras cf. manes Hall 

 Paleotrochus praecursor Clarke 

 Pleurotomaria capillaria Conrad 

 Loxonema noe Clarke 

 Loxonema var. 

 Styliolina fissurella Hall 

 Buchiola retrostriata (v. Buch) 

 Palaeoneilo muta Hall 

 Pterochacnia fragilis (Hall) 

 Atrypa reticularis Unite 



Ambocoelia umbonata Hall 

 Sp. cf. subumbona 

 Chonetes scitulus Hall 

 Liorhynchus mesacostalis Hall 

 L. globuliformis (Vanuxem) 

 Orthothetes sp. 



Orbiculoidea lodensis (Vanuxem) 

 Orbiculoidea, small form 

 Lingula spatulata Vanuxem 

 Cladochonus, abundant in the con- 

 cretions 



