342 CHARLES K. SWARTZ 



fauna at Catawissa, Pa. Clarke' and Prosser'' refer the Cowles Hill 

 fauna to the Chemung, Williams to the Ithaca. 



Spirifer mesacostalis fauna.^This fauna occurs above the preced- 

 ing and is present throughout the entire area. Its dominant forms are 

 Tropidoleptus carinatus, Spirifer mesacostalis, Spirifer marcyi and 

 many gastropods. The list of species observed is given on a pre- 

 ceding page. Many of these have marked Hamilton affinities. This 

 is especially true of the dominant brachiopods which include : 



Tropidoleptus carinatus (Conrad) 



Camarotoechia congregata (Conrad) 



Spirifer mesacostalis Hall (cf. S. consobrinus of the Hamilton) 



Spirifer marcyi Hall var. 



Cyrtina hamiltonensis Hall 



Goniophora glaucus Hall, Coleotus tenuicinctus Hall, and Phacops 

 rana are also suggestive of Hamilton affiinities. One species, Pro- 

 ductella lachrymosa is quoted by Williams^ as diagnostic of the Che- 

 mung in the Watkins, New York, quadrangle. Clarke, however, 

 quotes it as of frequent occurrence in the Ithaca further east.'^ All of 

 the forms specifically determined, save Cyclonema concinnum, are 

 found in the Ithaca fauna. ^ These facts seem sufficient to refer this 

 fauna to the Portage formation. In certain respects it resembles the 

 Enfield fauna of Williams which, according to him, lies in the Nunda 

 above the Ithaca and below the Chemung in the Watkins quadrangle. 

 The following species of the above list are quoted by him as character- 

 istic of that horizon: Tropidoleptus carinatus, Spirifer marcyi, Del- 

 thyrus mesacostalis, and numerous gastropods.^ It will be noted that 

 this fauna occupies a similar position in Maryland. 



Spirifer disjunctus fauna. — The lowest observed occurrence of 

 Spirifer disjunctus is in general 400-700 feet above the base of the 

 Spirifer mesacostalis fauna. With it are associated Douvillina cayuta 

 and Camarotoechia contracta, which have not been observed in the 

 preceding faunas. Spirifer mesastrialis is also abundant in the fauna 

 while it has been observed but rarely at lower horizons in Maryland. 



1 4gth Ann. Kept., for 1895, N. Y. State Museum, Vol. II, p. 39, 1898. 



2 lUd., p. 165. 



3 Journal of Geology, Vol. XV, p. 98, 1907. 



4 Bulletin 82, N. Y. State Museum, p. 64, 1905. s Ibid., pp. 61-65. 

 6 Journal of Geology, Vol. XV, p. 109, 1907. 



