Handbook of Paleontology 291 



shale is exposed along the Salmon river. These beds are 

 made up of predominant gray shales alternating with 

 sandstone beds which are often calcareous, rusty brown- 

 weathering and sometimes a foot or more thick. There 

 are also thin limestone bands. These and the calcareous 

 sandstone bands are highly fossiliferous. In the upper- 

 most Pulaski the gray noncalcareous sandstone beds be- 

 gin to predominate. The Pulaski shales are found in 

 north central New York, from Rome northward, and have 

 a thickness of about 400 feet. Some of the characteristic 

 fossils of these beds are the brachiopod Zygospira (?) 

 erratica; the cephalopod Ort hoc eras lamellosum; the pele- 

 cypods Modiodesma modiolare, Orthodesma nasutum, 

 Fterinea demissa, Byssonychia radiata, Clidophorus pla- 

 nulatus; and the trilobites Isotelus maximus pulaskiensis, 

 Cryptolithus lorrainensis and C. bellulus. A large brachi- 

 opod, Rafinesquina alternata na-suia and also R. mucro- 

 nata occur in the uppermost beds. The Pulaski shales 

 are a mud facies and therefore characterized by a large 

 number of pelecypods or lamellibranchs. Such a facies 

 is also termed a "lamellibranch" facies. 



The Oswego sandstone was described by Vanuxem 

 ('42) as the "Gray sandstone of Oneida/' and was earlier 

 designated the "Salmon River sandstone" because it oc- 

 curs at Salmon river capping the Pulaski shale. The fauna 

 of the last Lorraine zone has been traced (Ulrich and 

 Foerste) into undoubted Oswego sandstone in the cliff 

 at Salmon River falls, establishing the fact that there is 

 no lithologic break between the Pulaski and Oswego. 

 The Oswego sandstone thus is considered as the closing 

 phase of the Ordovician rather than one introducing the 

 Silurian. The sandstone occurs in Oswego, Oneida, 

 Lewis and Jefferson counties and then passes westward 



