FOSSILS OF THE TULLY LIMESTONE. 491 



Bronteus tullius Hall. 



Platyceras symmetricum, Hall (var.). 



Also representatives of the following genera: 



Amplexus, 

 Aulopora, 



Euomphalus (rare), 

 Pleurotomaria, 

 Loxonema (rare), 

 Conocardium (rare), 

 Schizodus (rare), 

 Orthoceras, 



Goniatites (rare), aud 

 Tentaeulites. 



Some other genera are represented, but the complete list of genera and 

 species, with descriptions and comparisons, is reserved for a future paper. 



What do these Tully forms testify as to their relation to the Cuboides 

 fauna of Europe ? 



The trilobites of the first two genera (named above) are Hamilton species, 

 traces of which are found still higher in the Chemung. The Bronteus ap- 

 pears to be unique and is closely allied to a form of the European Cuboides 

 zone (B. flabellifer Goldfi). 



Of the genera of gasteropods, corals, lamellibranchs, and cephalopods, 

 I will only say here that the species are either identical with or closely 

 allied to those of the Hamilton formation below, and the differences at 

 present recognized, on comparing them with their representatives in the 

 preceding zone, are not so great as the differences between the latter and 

 their European representatives of the middle Devonian. 



Again, of the brachiopods. the Atrypas, are indistinguishable from forms 

 occurring both below and above ; hence they are valueless in defining the 

 zone. The Oyrtina, the Ambocwlia, the Streptorhynclms, and the Spirifer 

 fimbriatus are seen below and above this zone,, and are also represented by 

 closely allied forms in Europe. 



The Chonetes aurora (figures 10, 11, plate 12) is characteristic of the zone 

 in New York, but the species is not known outside the state. It appears 

 to me clearly distinct from the Burlington Chonetes lor/ant, Norwood and 

 Pratten; hence it is of no value in correlating with the Cuboides zone. 



Spirifer mucronatus var. tulliensis is a well-defined variety, strictly inter- 

 mediate between S. mucronatus, which precedes it, aud S. mesoeostalis, which 

 follows it, in the central part of the region under discussion. It is as perfect 

 an example of a connecting link as one could wish. The Spirifer tullius is 

 a forerunner of S. mesostrialis of the following Ithaca fauna, and while it 



