60 J. 31. Clarke — Clymenia in Western New York. 



The ornamentation of our species (which may be termed 

 Clymenia (Cyrtoclymenia) Neapolitana, from its occurrence 

 in the Naples beds) restricts its comparison to three well 

 known species, namely : Clymenia spinosa Minister, C bino- 

 closa Minister, and C. sxibarmata Minister. The last may be 

 left out of consideration on account of important differences 

 in the mature suture. The other two species belong to the 

 same group, Cyrtoclymenim Giimbel (genus Cyrtoclymenia 

 Hyatt) and in C spinosa the figures given by Minister* and 

 the description and illustration by Giimbelf show a similar 

 structure and arrangement of the spinous processes on the 

 ventro-lateral slopes of the whorls. The intervals between 

 these on the earlier whorls are covered by fine concentric lines 

 bending slightly forward over the ventrum but they have not 

 the falciform curve of the striae in C. Neapolitana. Giimbel 

 described a specimen of that species (figures 2a, ft, on his 

 plate xvi) in which, over a portion of the last volution, the 

 spinous nodes are reduced to bundles of striae, strongly defined 

 over the inner margin of the whorl, but spreading and losing 

 their identity over the ventrum. In C. ftinodosa the ornamen- 

 tation is less like that of the American form but the flattened 

 ventrum is better defined and the suture more like that of C* 

 Neapolitana than is that of C. spinosa. 



The geological interest attaching to this fossil is very great. 

 The genus Clymenia has been, wherever found, a most impor- 

 tant horizon-marker of the uppermost Devonian. It appeared 

 abruptly and quickly attained a prolific and exceedingly variant 

 development. Hyatt observes that " the whole range of trans- 

 formations of the Goniatitinse are paralleled in this short series 

 (Clymeninse) whose principal differential characteristic lies in 

 the dorsal position of the siphon.";}; 



Kayser has shown that the Clymenia fauna occurring on the 

 summit of the Enkeberg in Westphalia, is of later date than 

 the Cypridinen-schiefer of Nehden (horizon of Goniatites 

 cnrvispina and Verneuili) and is therefore the topmost mem- 

 ber of the deep-sea upper Devonian series of the continent of 

 Europe. Wherever found it has maintained this time-value. 

 Bichter, Giimbel and Kayser have demonstrated its position in 

 its richest development in the Fichtelgebirge (Schubelhammer, 

 Gattenclorf, etc.). Tietzehas described it in Silesia (Grafschaft 

 Glatz), Siemiradski in Poland, Freeh in Cabrieres (Languedoc), 

 Stur, Stache, Hoernes and Freeh have established the horizon 

 in Graz (Styria), and Karpinsky and Tschernyschew have iden- 

 tified it in the Urals. In Cornwall (South Petherwin) species 



*Beitrag zur Petrefactenk. v, pi. 11, fig. 15. 



f Ueber Clymenien in den TJebergangsgebilden des Fichtelgebirges, p. 48, pi. 16,. 

 figs. 1, 2. 



X Proc. Boston Soc. loc. cit. 



