Clarke — Oneonta, Ithaca and Portage Groups. 



the withdrawal of the Ithaca fauna, about 500 feet higher in the strata.* 

 Aside from the occurrence about Ithaca and that at Greene the species lias 

 been found, I believe, only at Hait's quarry near Homer, and (as recorded 

 on a later page of this paper) near McGrawville, Cortland count}- ; in both 

 instances with but few specimens. 



This reappearance of Spirifer Iwvis at an horizon which cannot be less 

 than 1,200 feet above its first appearance and most profuse development in 

 the rock series of the Ithaca section, and several hundred feet above its last 

 appearance in that section, is remarkable and unexpected. Its association with 

 Le/ptost/rophia mueroriata shows that, as we have already suggested, the Ithaca 

 fauna is not yet wholly extinguished, though its relicts are here consorting 

 with predominant and more and more emphatic Chemung types. 



Their presence in this association can no more modify our conception of 

 the post-Portage age of this fauna than if they were altogether absent, or, 

 rather, the fact of their presence here, under certain structural modifications, 

 is very evidence of such age. 



Flag Gulf (Figure 4). This is a ravine lying three miles south of Greene 

 on the east side of the Chenango river. The succession of rocks and fossils 

 is as follows : 



The lowest exposure (1 ) is about seventy-five feet above the river and 

 consists of gray flags; no fossils observed. 



Above this are three feet of soft shales (2), followed by four feet of sand- 

 stone (3) ; no fossils were found here. 



At (4 ) are five feet of flags and shales containing : 



ScMzophoria impressa, large form. 



Prod uetella speciosa. 



Spirifer mttcronatits, small variety. 



Above (5) are six feet of soft shales with Spirifer mucronatus, small 

 variety. 



L&ptostropMa perplana, var. nervosa, typical Chemung form. 

 Actinopteria eta. 



At (6) are twelve feet of" sand}- shales with but few fossils, namely : 



Actinopteria eta. 



Gon iophora minor. 



Spirifer mitcronatus, small variety. 



* Mr. E. M. Kindle, in a publication entitled " The Relation of the Fauna of the Ithaca irroup to the Faunas of the Portage and 

 Chemung," (Bull. Amer. Palaeontology, No. (J, dated December 25, 18%) mentions the occurrence of this species at an horizon 130 

 feet below this upper S. ktits zone (p. 3(ii and refers to the abundance of the fossil at its later appearance (p. 29). See further note 

 on this paper on page 57. 



