Portage Stages of New York. 219 



sion by Professor S. G-. Williams in the same year,* and finally 

 so indicated by Dr. H. S. Williams in 1890.f 



The bearing of this horizon will be immediately appre- 

 ciated when we remember that Smyrna is in the Chenango 

 river valley, while Oxford is nineteen miles farther south in 

 the same valley near which place it is stated the Hamilton is 

 exposed. The fossiliferous zone near Oxford is well exposed 

 at Norwich and on the hills near North Norwich, but farther 

 north at Sherburne it is found only near the top of the high 

 hills and at Smyrna it is hardly reached at the summit of the 

 highest hills. Some of the species belong in the Portage and 

 many occur in the Hamilton, among which are those slightly 

 modified from the Hamilton forms. The recurrence of the 

 Hamilton species in the higher beds has probably led several 

 geologists to refer these rocks to the Hamilton stage, and to 

 ignore the clear and perfectly conclusive stratigraphic evidence 

 of their age. The most authoritative correlations of this zone 

 with the upper part of the Hamilton stage are indicated in the 

 following foot note.J 



The stratigraphic sequence and general correlation of the 

 Hamilton and Portage stages for Chenango and Otsego coun- 

 ties were described by the writer in 1887 ;§ but at this time it 



* Sixth An. Rep. State Geol. [N. T.] for 1886, p. 13 ; and see map facing p. 28. 



•f Bull. Geol. Soc. Am., vol. i, p. 489. 



\ In the Geol. Surv. N. T., Palaeontology : vol. v, Pt. I, Lamellibranchiata II, 

 1885, several species are reported from localities in this zone which is called 

 Hamilton; as Goniophora carinata (Con.) Hall, from Oneonta, p. 302 ; Microdon 

 (C ' ypricardella) complanatus Hall, below Norwich, p. 312; Nuculites cunei- 

 fonnis Con., at Oneonta, p. 326; Palceoneilo arata Hall, "shales of the Hamil- 

 ton group, near Norwich," p. 342; Prothyris planulata Hall, near Norwich, p. 

 460 ; P. lanceolata Hail. Norwich, p. 461 ; Phthonia nodicostata Hall, near 

 Oneonta, p. 474: and finally on p. 517 is the statement that the Oneonta sand- 

 stone " comes in at about the close of the Hamilton period, or more properly may 

 be regarded as the result of changes which terminated the conditions of the Ham- 

 ilton group," while on p. 518 the Upper Devonian of Otsego, Delaware, and Che- 

 nango counties is correlated as follows : 



" Catskill group. 



Chemung ;: 



Oneonta i Porta g e §' rou P- 



I Hamilton (Upper). 



Hamilton group." 



A similar statement in reference to the age of these rocks occurs in ibid. 

 Lamellibranchiata I, as Leptodesma Rogersi Hall is reported ' : in the shales of 

 the Hamilton group at Norwich, Chenango county," p. 177. Finally, in 1886, 

 Professor Hall made the following statement in reference to a section near Ox- 

 ford : " The results of the most recent investigations have served to substantiate my 

 previous published statements, and clearly show that the Oneonta sandstone rests 

 upon well marked Hamilton strata, and is succeeded by strata carrying the fossils 

 of the Chemung Group " (Fifth An. Rep. State Geologist [New York] for 1885, 

 p. 4). Also the section on p. 11 represents the lowest shales and sandstones as 

 belonging to the ,: Hamilton group," and mentions Spirifera mesastrialis, Para- 

 cyclas lirata, and Polceoneilo muta from these beds. 



§ The paper was read at the New York meeting of the Am. Assoc. Adv. Sci., and 

 an abstract published in vol. xxxvi, p. 210. 



