372 



PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



run into the Devonian system, evidently heralding new mineral and 

 vital conditions. 



Fossils occurrent in Europe. — These are 1 8 in number ; or more 

 than one-third of the whole. All the 14 marked with an * are En- 

 glish also. They are — 



Atrypa tumida* (S.f); A. Didyma* (S.) ; Leptama depressa* (W.%, S.), 

 L. (Stroph.)pecten* (S.); Orthis hybrida* (W., S.), O. orbicularis* (S.), 

 O. resupinata* (S.) ; Pentamerus galeatus* ( W., S.) ; Spirifer bilobus ( W., 

 De Vern.), S. plicatus* (W., S.) ; Terebratula borealis* (De Vern., S.), T. 

 deflexa (IV., De Vern.), T. Stricklandi* (S.\, T. n. s.* (S.) ; Atrypa reti- 

 cularis* (W., -L.§, S.) ; Phacops Hausmanni (De Vern.), P. macrophthal- 

 mus (Eifel, De Vern.); Avicula naviformis* (S.),=18. 



Fossils recurrent in New York. — These are only eleven : — ■ 



Leptsena depressa (also Devonian) ; Orthis resupinata (also Devonian) ; 

 Spirifer macropleurus ; Atrypa reticularis (also Devonian) ; Terebratula 

 Wilsoni ; Pentamerus galeatus ; Euomphalus profundus ; Avicula navi- 

 formis ; Theca Forbesii; Lepocrinites Gebhardii ; Cornulites serpularius. 



They are all from below, except three, which pass upwards. 

 (Table No. VI. shows the palseontological relations of the four 

 limestones above mentioned.) 



The Devonian System of the State of New York. 

 Oriskany Sandstone. 



Mineral Character. — This rock, the Potsdam Sandstone, and the 

 Calciferous Sandstone, are the only strata, at least in and about 

 Central New York, according to Vanuxem (p. 123), which present 

 unaltered the sand of the Crystalline or Hypogene formations, as it 

 appears when pure. 



The Oriskany Sandstone is a coarse, rather loosely cemented sili- 

 ceous sandstone, such as is derived from granite, gneiss, or mica- 

 slate. It is yellowish-white, and contains flat chert-nodules and 

 druses. 



In the upper part of the rock are many concretions of dark, com- 

 pact, and crystalline sandstone, from one to six inches in diameter ; 

 and it is full of cavities left by dropped fossils. Hall supposes that 

 much of this rock has once been calcareous, from the number of its 

 pores and holes, and from the abundance of its fossils ; and it is now 

 occasionally calcareous in a slight degree (De Verneuil, loc. cit. p. 

 657). 



Place. — This sandstone holds a fixed position in the New York 

 series, and is readily traced by its composition and characteristic fos- 

 sils, which individually are numerous and distinct. 



Oriskany Sandstone is confined to Eastern and Central New York, 

 being absent in the west of the State, as well as from the countries 

 westward towards the River Mississipi (De Verneuil). 



"It is deposited," says James Hall, "in depressions due either 



f S. stands for Daniel Sharpe. 

 § L., Upper Ludlow. 



X W., Wenlock Limestone. 



