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306 ANNALS NEW YORK ACADEMY OF SCIENCES 



of the Khipidomellas, but if reliance may be placed on the size and shape 

 of the muscle scars, which are usually regarded as good specific characters 

 in this group, I may say positively that the Bedford form is not Ehipi- 

 domella burlingtonensis (which was described as a variety of michelini 

 and is the most probable species indicated by that name which was orig- 

 inally applied to a European form). Chonetes logani is the form which 

 I called Chonetes n. sp., and which was beyond question wrongly identi- 

 fied with Norwood and Pratten's species. For Syringothyris typa, I 

 have adopted Schuchert's identification, S. carteri. When Newberry 

 wrote, and when Herrick wrote for that matter, the genus Syringothyris 

 was regarded as a diagnostic Carboniferous type and very justly, so far 

 as the facts were then known, but it has subsequently been found that 

 the genus occurs abundantly in direct association with Spirifer disjunc- 

 tus in the "Bradfordian" rocks of northwestern Pennsylvania. Since 

 S. disjunctus has always been regarded as being as emphatic a marker of 

 the Devonian as Syringothyris was of the Carboniferous, it is clear that 

 the evidence of either type is disqualified for deciding the question at 

 issue. Schuchert 12 has even described a species of Syringothyris from 

 the middle Devonian of Missouri, and furthermore a tendency to develop 

 the syrinx seems to be manifested in several Devonian species of Spirifer, 

 so that it would seem as if the evidence of S. disjunctus should be es- 

 teemed of greater weight in favor of the Devonian than that of Syringo- 

 thyris in favor of the Carboniferous age of the "Bradfordian" strata. 



Newberry's Spiriferina solidirostris is the Delthyris n. sp. of my list. 

 It is absolutely certain that this form is not the Kinderhook species 

 S. solidirostris and almost equally certain that it is not a Spiriferina at 

 all. It has, it is true, the general expression and the median septum 

 which are found in Spiriferina and which are also found in the group of 

 Spirifers to which the title Delthyris has been applied, but it does not 

 possess the punctate shell structure which is an indispensable character 

 of Spiriferina. The form in question is not rare in the Bedford shale 

 and I have been able to examine a considerable number of specimens. 

 This I have done both with a hand lens and with a compound microscope 

 without success in finding the punctate structure which is usually a feat- 

 ure easily detected in species really belonging to the genus. Thus, I am 

 forced to conclude that the form is not a Spiriferina, which is a typical 

 Carboniferous genus, but that it is a Delthyris, which is an almost equally 

 typical Devonian one. 



I have thus traversed all the forms thought by Newberry or by Her- 

 rick to indicate a Carboniferous age for the Bedford fauna, and their 



12 Am. Jour. Sci., vol. 30, p. 223. 1910. 



