GEOLOGIC MAP OF THE BUFFALO QUADRANGLE 15 



at the base of the formation. The hmestones are, on the contrary, 

 highly fossihferous and often entirely composed of shells. The 

 fauna of the Marcellus shales and limestones of Lancaster has 

 been thoroughly studied by Wood,^ who records as the most 

 common forms of the shale Styliolina fissurella 

 Hall, Chonetes mucronatus Hall, Strophalosia 

 truncata Hall, Pterochaenia fragilis Hall and 

 Liorh5^nchus limitare Vanuxem. The lowest shale 

 exposed proved to contain abundant ostracod valves, belonging 

 to the species Isochilina (?) fabacea Jones and 

 Primitiopsis punctulifera Hall. 



Stafford limestone 



On Flint creek in the town of Phelps, Ontario co., the Marcellus 

 shales are capped by a 4 inch layer of dark chocolate limestone 

 which is very hard when fresh but breaks easily into angular 

 fragments after exposure. It is not known farther east but increases 

 westward from 2 feet or more at the Livonia salt shaft to nearly 4 feet 

 at Stafford, where it is well exposed and whence the name is derived, 

 and to 8 feet, 4 inches at Lancaster, Erie co. The record of the 

 Smoke's creek well makes it even 15 feet thick at that point. 

 There are no exposures of the entire formation on this quadrangle 

 but the upper layers outcrop to the thickness of nearly 6 feet in 

 the bed of Buffalo creek opposite the end of the Winchester road, 

 I mile east of South Buffalo and i| miles south of the junction 

 with Cayuga creek, at which latter point there is a small exposure 

 of Onondaga limestone. 



The Stafford limestone is here a compact bluish gray limestone, 

 mostly in thick layers and bearing a strong resemblance to the 

 Onondaga limestone by the admixture in considerable proportion 

 of dark chert in nodules and nodular layers. It has been found 

 in excavations at several places southwest from this exposure but 

 nowhere comes to the surface and its precise position on the lake 

 shore is not known, the bed being completely buried under heavy 

 drift cover. 



Besides the exposures previously mentioned it appears in the 

 east bank of the Oatka river at Leroy and along the outlet of 

 Conesus lake at Little ville near Avon. 



Fossils are abundant in the Stafford limestone at Lancaster, 

 specially in the upper part and some layers are entirely made up of 



IN. Y. State Mus. BuL 49. 1901, p. 139-81. 



