Report of the State Geologist. 



423 



tropods pass into the overlying formations, especially the Oriskany 

 sandstone, while others are represented in this formation by analogous 

 forms. If the fauna of the Lower Helderberg reveals close alliances 

 with our Hercynian, those of the overlying formations bear still 

 stronger affiliations. 



"In the immediately following thick arenaceous deposits of the 

 Oriskany, Cauda-galli and Schoharie grit (the last of which does not 

 exist in Canada), the similarity with the Hercynian is not so clearly 

 evident as in the overlying limestones, and indeed from their wholly 

 distinct petrographical character nothing else is to be expected. 

 Nevertheless this similarity can not be overlooked and the Devonian 

 character here is still more clearly developed than in the Lower 

 Helderberg. In the Oriskany sandstone, besides the first fishes, 

 appear large, coarse-ribbed, broad-winged Spirifers of true Devonian 

 habit; also species with simple or dichotomizing ribs, related to the 

 well-known Sp. aperturatus and Verneuili (arenosus, Conr.), a con- 

 siderable number of Rensselaerias and another genus of Terebratulids, 

 Centronella; further, numerous great species of Pterinea, and Orthis? 

 hipparionyx, that is, forms which indicate a Devonian fauna of the 

 general expression of our Rhenish Spiriferensandstein fauna. An 

 Hercynian cast is given to this Oriskany fauna by the contemporaneous 

 existence of Dalmanites of the pleuroplyx-gvowp, Calymene Blumen- 

 bachi, and a number of Capulids. In the Schoharie grit, in addition 

 to the forms named is, on one hand the Devonian genus Gyroceras, 

 on the other a Trochoceras. 



"Finally, in regard to the Upper Helderberg group, we here also 

 encounter a Devonian fauna, just as undoubtedly allied to our Hercy- 

 nian. The Devonian character is expressed in the appearance of the 

 genus Cryphseus, by Gyroceras and ornamented Cyrtocerata, by the 

 first representative of the Goniatites (mithrax, Hall, of the group of 

 Simplices), by the Brachiopod fauna, in which, besides the Devonian 

 Spirifers of the Oriskany, are numerous Terebralutid genera (Rens- 

 sekeria Terebratula, Centronella Cryptonella), a Camarophoria, and 

 several species of Productus; by the coral fauna with Calceola, 

 Michelinia, Pleurodictyum (?), Heliophyllum, Phillipsastrsea, etc., 

 and besides, a great number of species in common with, or analogous 

 to those of the Hamilton shale. On the other hand, the relation to 

 the Hercynian is demonstrated in about a dozen great Dalmanites 

 which again belong essentially to the pleuroj)tyx-grou-p, by a great 

 Calymene, allied to Blumenbachi, a half-dozen species of Trochoceras, 

 and Hercoceras (?), several great species of Nautilus suggesting forms 

 from the Bohemian etage E., Dictyograptus (splendens Billings) and 



