300 C. SCHUCHERT — LOWER HELDERBERG-ORISKANY FORMATIONS 



upward into the Onondaga or Corniferous. The Lower and Upper Oris- 

 kany may have a little more than 23 per cent of species in common, but 

 this percentage will probably be modified when Doctor Clarke has fin- 

 ished his work on the Bee raft Mountain fauna. These figures show 

 conclusively that the Helderbergian, Oriskanian, and Onondagan are 

 very intimately related ; also the correctness of the conclusion of Sharpe 

 and de Verneuil (1847), and later of all American geologists, that the 

 Oriskany is Devonic. 



In conclusion, the English, Continental, and American Lower and 

 Middle Devonic horizons are tabulated on page 297. 



Local Development and Faunas of the Oriskanian 

 upper oriskany of new york 



The Oriskany formation was first observed in New York, and for that 

 matter in North America, by Professor Amos Eaton, who named it the 

 "Shell Grit." Vanuxem, the state geologist of the third geological dis- 

 trict of New York, appears to be the next to notice this formation, for in 

 that district the Oriskany is well shown. In 1838* he described it as 

 the " White Sandstone. — Characterized by large species of Orthis [Hip- 

 parionyx] and Delthyris " [Spirifer]. In the following year Conrad f 

 writes of it as the " Grey Brachiopodous sandstone" of the ''Medial 

 Silurian strata," characterized by Atrypa elongata (Rensselxria ovoides 

 Eaton) and Delthyris arenosa (Spirifer arenosus Conrad). 



In 1839, this formation received the name b} T which it has since been 

 known. In that year Vanuxem J stated that "the omission or absence 

 of these two series to the west [Delthyris shale of the Lower Helderberg 

 and the Cauda-galli] causes the next series of layers to repose imme- 

 diately upon the Waterlime group. This is the white sandstone noticed 

 on the hill at the falls of Oriskany, and for the present may be called 

 the Oriskanjr sandstone. This sandstone is well known to extend over 

 man)'' of the states, occupying, like all geological masses, a fixed position 

 in the whole series, but is exceedingly variable in thickness. According 

 to the report of the state geologist of Pennsylvania, it is there 700 feet 

 thick [this probably includes the Esopus grit; the Oriskany appears 

 not to exceed 300 feet]. At Oriskany falls [it is] about 20 feet, on the 

 road from Elbridge to Skaneateles, it is over 30 feet. At the quarries 

 near Auburn, it is from a few inches to about 21 feet; and at Split- Rock, 

 near S} r racuse, it shows itself in some parts by a mere sprinkling of sand, 



♦ Second Ann. Rept. Geol. Survey, Third Disk N. V., is:'>8, p. 285. 



t Second Ann. Rept. Pal. Dept., Survey N. Y., 1839, i>. 62. 



J Third Ann. Rept. Geol. Survey. Third Dist. N. Y., 1839, p. 273. 



