262 c. SCHUCHERT — LOWES H ELDERBERG-ORISK AN Y FORMATIONS 



as a certain equivalent of the Lower Coblenzian, and probably also of 

 the Siegen grauwacke. This view, joined to that of the writer's, makes 

 the Kercyn fauna of the Lower Wieder Schieferthe probable equivalent 

 of the American Oriskany, although it may occupy a somewhat younger 

 position in the time scale. 



Another related fauna and one derived from calcareous beds is that 

 described by Barrois* from the hamlet of Erbray, in the lower Loire- 

 On examining the plates illustrating this fauna, it soon becomes appar- 

 ent that the Erbray fauna lias the general aspect of the Hartz Hercyn, 

 but the faunal assemblage is a different one and has a younger appear- 

 ance, which is due to the scarcity of orthids, being almost restricted to 0. 

 (Rhipidomella) palliata, a local and distinct development. The Stropheo- 

 dontas are rather those of the American Middle Devonic, and the same 

 is true of man}'' of the Rhynchonellas, athyroids, and centronelloids. 

 The Spirifers, as a rule, find their analogues in the Oriskany and Middle 

 Devonic, while the large Megalanteris inornata and M. deshayesii point to 

 the Oriskany. Indications of the older faunas occur in the strongly 

 plicated pentameroids, some of the Rhynchonellas, the Meristellas, and 

 Spirifer bisulcata. A decided Devonic aspect is marked in the trilobites, 

 for CryphivAis is here well developed and the Dalmanites (Odontocheile) 

 section is absent. The platyceroids agree both with the Lower Helder- 

 berg and Oriskany, while the other gastropods accord with forms best 

 developed in the Siluric. The great development of Conocardium in 

 the Erbray fauna gives it its character, yet the forms are all small, and 

 therefore do not have the aspect of higher Devonic species. The abun- 

 dance of cup corals and Acervularia is also a decided characteristic of 

 American Middle Devonic faunas. 



It is unsafe to make definite correlations when faunas are so different 

 as that of Erbray and those of the American Lower Devonic. It is true 

 that the Erbray fauna and that of the Lower Helderberg are from lime- 

 stones, but the Oriskany fauna is nearly everywhere found in a coarse 

 sandstone, while practically nothing is known of the life of the Cauda- 

 galli (— Esopus). However, the above summary of the Erbray fauna 

 shows that the development is unlike that of the American Lower Helder- 

 berg. While the latter brings to mind some of Erbray, still the develop- 

 mental progression is rather that seen in the Oriskany, and probably also 

 of the time interval represented by the Cauda-galli. 



Recently Freeh f has discussed the position of this fauna and points 

 out that there are three fossil zones the exact relation of which, one to 

 another, is not yet fully established. He correlates the Erbray fauna 



* Faune du Calcaire d'Erbray ; font. ;i l'6tude «ln Terrain devouien. Mem. Soc. geol. du Nord, 

 iii, April, L889. 

 f Lethsea geognostica, p. 195, and table xiii. 



